Unit 13 - Circle Workbook 13 - Circle... · The diameters of (L and (M are 20 and 13 units,...
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Transcript of Unit 13 - Circle Workbook 13 - Circle... · The diameters of (L and (M are 20 and 13 units,...
Geometry
Circles
Name _________________
Period _____________
1
!
"
Date: ______________________
Notes
Section 10 – 1 & 10 – 2: Circumference, Arcs, and Angles
Circle – a set of _________ equidistant from a given point called the __________ of the
circle
Circumference:
Example #1:
a.) Find C if r = 13 inches. b.) Find C if d = 6 millimeters.
c.) Find d and r to the nearest hundredth if C = 65.4 feet.
Central Angle – an angle that has the center of the circle as its vertex, and its sides
contain two radii of the circle
Minor Arc – arc degree measure equals the measure of the ____________ angle and is
less than 180 degrees
Major Arc – arc degree measure equals 360 minus the measure of the ___________ arc
and is greater than 180 degrees
2
#
Semicircle – arc degree measure equals __________
Example #1: Refer to circle T.
a.) Find .m RTS!
b.) Find .m QTR!
Example #2: In circle P, 46m NPM! " , PL bisects ,KPM! and .OP KN# Find each
measure.
a.) m OK
b.) m LM
c.) m JKO
3
© Glencoe/McGraw-Hill Glencoe Geometry
For Exercises 125, refer to the circle.
1. Name the circle. 2. Name a radius.
3. Name a chord. 4. Name a diameter.
5. Name a radius not drawn as part of a diameter.
6. Suppose the radius of the circle is 3.5 yards. Find the diameter.
7. If RT 5 19 meters, find LW.
The diameters of (L and (M are 20 and 13 units, respectively.
Find each measure if QR 5 4.
8. LQ 9. RM
The radius, diameter, or circumference of a circle is given. Find the missing
measures to the nearest hundredth.
10. r 5 7.5 mm 11. C 5 227.6 yd
d 5 , C < d < , r <
Find the exact circumference of each circle.
12. 13.
SUNDIALS For Exercises 14 and 15, use the following information.
Herman purchased a sundial to use as the centerpiece for a garden. The diameter of the
sundial is 9.5 inches.
14. Find the radius of the sundial.
15. Find the circumference of the sundial to the nearest hundredth.
40 mi
42 mi
K24 cm
7 cm
R
PQL R
MS
L
W
R
S
T
Practice
Circles and Circumference
NAME ______________________________________________ DATE ____________ PERIOD _____
10-110-1
4
NAME ___________________________ Period _________ Date _____________
Today you will be INSCRIBING polygons. Follow the directions carefully. Mark all points
clearly and answer questions asked.
Part 1
Draw !O in the area below.
Draw ABC∆ inscribed in !O with BC as a diameter.
What is the m BC _______________________
What is BACm∠ __________
What type of triangle is ABC∆ ? ________________
Is BACm∠ = m BC _____________
How do the measures of BAC∠ and BC compare? _____________________________
Write a conjecture that compares the inscribed angle and the arc it intercepts:
5
Part 2
You will draw a regular pentagon (called PENTA) by following the directions:
• How big is one central angle of a pentagon? (Remember we did total circle divided by
number of sides) _____________
• Draw an angle PKE∠ that is the measure of one central angle using the protractor.
• Using the same vertex point (K), draw an adjacent angle to PKE∠ also the same measure
using the protractor.
• Repeat this for all 5 angles of the Pentagon
• Draw a new circle called !K using the point K of the angles you drew as the center using
the compass.
• Complete the Pentagons by connecting the points (chords) where the circle and the angle
sides intersect. Call these points PENTA.
How big is each central angle of Pentagon PENTA? ___________
How big is each vertex angle of Pentagon PENTA? __________-
What is the measure of each of the congruent arcs? __________
Complete the measures below:
APEm∠ _______ m PE _________ m ENA _________
PENm∠ _______ m EN _________ m NTP __________
ENTm∠ _______ m NT _________ m TAE __________
NTAm∠ _______ m TA _________ m APN __________
TAPm∠ _______ m AP _________ m PET __________
APE∠ forms which arc? _______
APE∠ PEN∠ forms which arc? _______
APE∠ TAP∠ forms which arc? _______
How does the inscribed angle compare to the arc it forms?
6
© Glencoe/McGraw-Hill Glencoe Geometry
ALGEBRA In (Q, AwCw and BwDw are diameters. Find each
measure.
1. m/AQE 2. m/DQE
3. m/CQD 4. m/BQC
5. m/CQE 6. m/AQD
In (P, m/GPH 5 38. Find each measure.
7. mEFC
8. mDEC
9. mFGC
10. mDHGC
11. mDFGC
12. mDGEC
The radius of (Z is 13.5 units long. Find the length of each arc
for the given angle measure.
13. QPTC
if m/QZT 5 120 14. QRC
if m/QZR 5 60
15. PQRC
if m/PZR 5 150 16. QPSC
if m/QZS 5 160
HOMEWORK For Exercises 17 and 18, refer to the table,
which shows the number of hours students at Leland
High School say they spend on homework each night.
17. If you were to construct a circle graph of the data, how many
degrees would be allotted to each category?
18. Describe the arcs associated with each category.
Homework
Less than 1 hour 8%
1–2 hours 29%
2–3 hours 58%
3–4 hours 3%
Over 4 hours 2%
Q
Z
T
P
R
S
F
P
D
EG
H
(5x 1 3)8
(6x 1 5)8 (8x 1 1)8
QA
B
C
DE
Practice
Angles and Arcs
NAME ______________________________________________ DATE ____________ PERIOD _____
10-210-2
7
8
© Glencoe/McGraw-Hill Glencoe Geometry
The Four Color Problem
Mapmakers have long believed that only four colors are necessary todistinguish among any number of different countries on a plane map.Countries that meet only at a point may have the same color providedthey do not have an actual border. The conjecture that four colors aresufficient for every conceivable plane map eventually attracted theattention of mathematicians and became known as the “four-colorproblem.” Despite extraordinary efforts over many years to solve theproblem, no definite answer was obtained until the 1980s. Four colorsare indeed sufficient, and the proof was accomplished by makingingenious use of computers.
The following problems will help you appreciate some of thecomplexities of the four-color problem. For these “maps,” assume thateach closed region is a different country.
1. What is the minimum number of colors necessary for each map?
a. b. c.
d. e.
2. Draw some plane maps on separate sheets. Show how each can be colored using four colors. Then determine whether fewer colors would be enough.
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-110-1
9
© Glencoe/McGraw-Hill Glencoe Geometry
Curves of Constant Width
A circle is called a curve of constant width because no matter how
you turn it, the greatest distance across it is always the same.
However, the circle is not the only figure with this property.
The figure at the right is called a Reuleaux triangle.
1. Use a metric ruler to find the distance from P to
any point on the opposite side.
2. Find the distance from Q to the opposite side.
3. What is the distance from R to the opposite side?
The Reuleaux triangle is made of three arcs. In the example
shown, PQC
has center R, QRC
has center P, and PRC
has
center Q.
4. Trace the Reuleaux triangle above on a piece of paper and
cut it out. Make a square with sides the length you found in
Exercise 1. Show that you can turn the triangle inside the
square while keeping its sides in contact with the sides of
the square.
5. Make a different curve of constant width by starting with the
five points below and following the steps given.
Step 1: Place he point of your compass on
D with opening DA. Make an arc
with endpoints A and B.
Step 2: Make another arc from B to C that
has center E.
Step 3: Continue this process until you
have five arcs drawn.
Some countries use shapes like this for coins. They are useful
because they can be distinguished by touch, yet they will work
in vending machines because of their constant width.
6. Measure the width of the figure you made in Exercise 5. Draw
two parallel lines with the distance between them equal to the
width you found. On a piece of paper, trace the five-sided figure
and cut it out. Show that it will roll between the lines drawn.
A
C
B
D
E
P Q
R
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-210-2
10
$
Date: _____________________
Notes
Section 10 – 3: Arcs and Chords
! The ________________ of a chord are also endpoints of an _______.
Arcs and Chords
Theorem 10.2
Ex:
: In a circle, two ___________ arcs are congruent if and only
if their corresponding ____________ are congruent.
! The chords of _______________ arcs can form
Inscribed and Circumscribed
a _______________.
! Quadrilateral ABCD is an ______________ polygon
because all of its _____________ lie on the circle.
! Circle E is ___________________ about the polygon
because it contains all of the vertices of the _______________.
Theorem 10.3
Ex:
: In a circle, if the diameter (or radius) is ________________
to a chord, then it ___________ the chord and its arc.
11
%
Example #1: Circle W has a radius of 10 centimeters. Radius WL is
perpendicular to chord HK , which is 16 centimeters long.
a.) If mHL = 53, find mMK.
b.) Find JL.
Theorem 10.4: In a circle, two ___________ are congruent if and only if
they are __________________ from the center.
Example #2: Chords EF and GH are equidistant from the center. If the
radius of circle P is 15 and 24EF ! , find PR and RH.
12
Name ___________________________________________ Period ______ Date _________
For this exercise you will need a ruler and a piece of string. Use the ruler to draw the straight
lines and measure them. Use the string to measure the arcs and then use the ruler to measure
the string length you found for the arc measure.
In the circle given (� H),
1. Draw a chord AB
2. Draw another chord the same size as AB and call it CD
3. How far is AB from the center H? ________
4. How far is CD from the center H? ________
5. Draw a diameter FG that is ⊥ to AB at a point you call P
6. What is the length of AP ? ________
7. What is the length of BP ? _________
8. Use the string to find the length of AB _________
9. Use the string to find the length of AP _________
10. Use the string to find the length of BP _________
11. Use the string to find the length of CD _________
13
© Glencoe/McGraw-Hill Glencoe Geometry
In (E, mHQC
5 48, HI 5 JK, and JR 5 7.5. Find each measure.
1. mHIC
2. mQIC
3. mJKC
4. HI
5. PI 6. JK
The radius of (N is 18, NK 5 9, and mDEC
5 120. Find each
measure.
7. mGEC
8. m/HNE
9. m/HEN 10. HN
The radius of (O 5 32, PQC
> RSC
, and PQ 5 56. Find each
measure.
11. PB 14. BQ
12. OB 16. RS
13. MANDALAS The base figure in a mandala design is a nine-pointed
star. Find the measure of each arc of the circle circumscribed about
the star.
O
QR
P B
S
A
N
ED
X
Y
K
G
H
EK
J
R
I
S
H
Q
P
Practice
Arcs and Chords
NAME ______________________________________________ DATE ____________ PERIOD _____
10-310-3
14
© Glencoe/McGraw-Hill Glencoe Geometry
Patterns from Chords
Some beautiful and interesting patterns result if you draw chords toconnect evenly spaced points on a circle. On the circle shown below,24 points have been marked to divide the circle into 24 equal parts.Numbers from 1 to 48 have been placed beside the points. Study thediagram to see exactly how this was done.
1. Use your ruler and pencil to draw chords to connect numbered
points as follows: 1 to 2, 2 to 4, 3 to 6, 4 to 8, and so on. Keep dou-
bling until you have gone all the way around the circle.
What kind of pattern do you get?
2. Copy the original circle, points, and numbers. Try other patterns
for connecting points. For example, you might try tripling the first
number to get the number for the second endpoint of each chord.
Keep special patterns for a possible class display.
37
13
1
25
7 3143 19
44 20
45 21
42 18
41 17
40 16
39 1
5
38 1
4
46 2
2
47 2
3
48 2
4
12 3
6
11 35
10 3
4
9 33
8 32
6 30
5 294 28
3 2
72 2
6
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-310-3
15
&
Date: _____________________
Notes
Section 10 – 4: Inscribed Angles
If an angle is ______________ in a circle, then the measure of the angle equals
______________ the measure of its intercepted arc (or the measure of the
__________________ arc is ___________ the measure of the inscribed angle).
Inscribed Angles
Ex:
Example #1: In circle O, mAB = 140, mBC = 100, and mAD = mDC. Find the
measures of the numbered angles.
16
'
Angles of Inscribed Polygons
Theorem 10.7
Ex:
: If an inscribed angle intercepts a semicircle, the angle is a
____________ angle.
Example #2: Triangles TVU and TSU are inscribed in circle P, with SUVU ! . Find the
measure of each numbered angle if 2 9m x" # $ and 4 2 6m x" # $ .
Example #3: Quadrilateral ABCD is inscribed in circle P. If 80m B" # and 40m C" # ,
find m A" and m D" .
17
© Glencoe/McGraw-Hill Glencoe Geometry
In (B, mWXC
5 104, mWZC
5 88, and m/ZWY 5 26. Find the
measure of each angle.
1. m/1 2. m/2
3. m/3 4. m/4
5. m/5 6. m/6
ALGEBRA Find the measure of each numbered angle.
7. m/1 5 5x 1 2, m/2 5 2x 2 3 8. m/1 5 4x 2 7, m/2 5 2x 1 11,
m/3 5 7y 2 1, m/4 5 2y 1 10 m/3 5 5y 2 14, m/4 5 3y 1 8
Quadrilateral EFGH is inscribed in (N such that mFGC
5 97,
mGHC
5 117, and mEHGC
5 164. Find each measure.
9. m/E 10. m/F
11. m/G 12. m/H
13. PROBABILITY In (V, point C is randomly located so that it
does not coincide with points R or S. If mRSC
5 140, what is the
probability that m/RCS 5 70?
V
R
S
C
1408
708
NF
E
H
G
RB
A
D
C
1
2
3
4
U
J
G
I
H
1 3
42
B
ZY
XW
1
2
3 4
5
6
Practice
Inscribed Angles
NAME ______________________________________________ DATE ____________ PERIOD _____
10-410-4
18
© Glencoe/McGraw-Hill Glencoe Geometry
Formulas for Regular Polygons
Suppose a regular polygon of n sides is inscribed in a circle of radius r. The
figure shows one of the isosceles triangles formed by joining the endpoints of
one side of the polygon to the center C of the circle. In the figure, s is the length
of each side of the regular polygon, and a is the length of the segment from C
perpendicular to AwBw.
Use your knowledge of triangles and trigonometry to solve the
following problems.
1. Find a formula for x in terms of the number of sides n of the polygon.
2. Find a formula for s in terms of the number of n and r. Use trigonometry.
3. Find a formula for a in terms of n and r. Use trigonometry.
4. Find a formula for the perimeter of the regular polygon in terms of n and r.
A
C
a
s
s
2
r r
x° x°
Bs
2
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-410-4
19
Date: _____________________
Notes
Section 10 – 5: Tangents
!
Tangents
Tangent
! The point of intersection is called the _________ ___ ____________.
– a line in the plane of a ___________ that intersects the circle in
exactly one ____________.
Ex:
Theorem 10.9
Ex:
: If a line is ______________ to a circle, then it is
______________________ to the ____________ drawn to the point of
_____________.
Example #1: RS is tangent to circle Q at point R. Find y.
20
)
Theorem 10.10
Ex:
: If a _________ is perpendicular to a radius of a circle at its
______________ on the circle, then the line is _____________ to the
circle.
Example #2: Determine whether the given segments are tangent to the given
circles.
a.) BC b.) WE
Theorem 10.11
Ex:
: If two ______________ from the same exterior point are
_____________ to a circle, then they are ________________.
21
*
Example #3: Find x. Assume that segments that appear tangent to circles are
tangent.
Example #4: Triangle HJK is circumscribed about circle G. Find the perimeter of
!HJK if NK = JL + 29.
22
© Glencoe/McGraw-Hill Glencoe Geometry
Determine whether each segment is tangent to the given circle.
1. MwPw 2. QwRw
Find x. Assume that segments that appear to be tangent are tangent.
3. 4.
Find the perimeter of each polygon for the given information. Assume that
segments that appear to be tangent are tangent.
5. CD 5 52, CU 5 18, TB 5 12 6. KG 5 32, HG 5 56
CLOCKS For Exercises 7 and 8, use the following
information.
The design shown in the figure is that of a circular clock
face inscribed in a triangular base. AF and FC are equal.
7. Find AB.
8. Find the perimeter of the clock.
F
B
A
D E
C7.5 in.
2 in.
12
6
3
2
48
1011 1
57
9
L
HG
KT
B D
U
V
C
P
T
S10
15
x
L
T
U
S
7x 2 3
5x 1 1
P
R
Q
14
50
48L
M
P
20 21
28
Practice
Tangents
NAME ______________________________________________ DATE ____________ PERIOD _____
10-510-5
23
© Glencoe/McGraw-Hill Glencoe Geometry
Tangent Circles
Two circles in the same plane are tangent circles
if they have exactly one point in common. Tangent
circles with no common interior points are externally
tangent. If tangent circles have common interior
points, then they are internally tangent. Three or
more circles are mutually tangent if each pair of
them are tangent.
1. Make sketches to show all possible positions of three mutually tangent circles.
2. Make sketches to show all possible positions of four mutually tangent circles.
3. Make sketches to show all possible positions of five mutually tangent circles.
4. Write a conjecture about the number of possible positions for n mutually tangent circles
if n is a whole number greater than four.
Externally Tangent Circles
Internally Tangent Circles
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-510-5
24
Date: _____________________
Notes
Section 10 – 6: Secants, Tangents, and Angle Measures
Secant
Ex:
– a line that intersects a circle in exactly _________ points
Theorem 10.12: (Secant-Secant Angle) Theorem 10.13:
Ex: Ex:
(Secant-Tangent Angle)
Theorem 10.14:
Two Secants Secant-Tangent Two Tangents
Example #1: Find 3!m and 4!m if mFG = 88 and mEH = 76.
25
!!
Example #2: Find m RPS! if mPT = 144 and mTS = 136.
Example #3: Find x.
Example #4: Use the figure to find the measure of the bottom arc.
Example #5: Find x.
26
© Glencoe/McGraw-Hill Glencoe Geometry
Find each measure.
1. m/1 2. m/2 3. m/3
Find x. Assume that any segment that appears to be tangent is tangent.
7. 8. 9.
10. 11. 12.
9. RECREATION In a game of kickball, Rickie has to kick the
ball through a semicircular goal to score. If mXZC
5 58 and
the mXYC
5 122, at what angle must Rickie kick the ball
to score? Explain.
goal
B(ball)
X
Z Y
378
x 8
528
x 8
638
x 8
5x 8
628 1168
x 8
598
158
2x 8
398
1018
x 8
2168
3
1348
2
568
1468
1
Practice
Secants, Tangents, and Angle Measures
NAME ______________________________________________ DATE ____________ PERIOD _____
10-610-6
27
© Glencoe/McGraw-Hill Glencoe Geometry
Orbiting Bodies
The path of the Earth’s orbit around the sun is elliptical. However, it is often viewed
as circular.
Use the drawing above of the Earth orbiting the sun to name the line or segment
described. Then identify it as a radius, diameter, chord, tangent, or secant of
the orbit.
1. the path of an asteroid
2. the distance between the Earth’s position in July and the Earth’s position
in October
3. the distance between the Earth’s position in December and the Earth’s position
in June
4. the path of a rocket shot toward Saturn
5. the path of a sunbeam
6. If a planet has a moon, the moon circles the planet as the planet circles the sun. To
visualize the path of the moon, cut two circles from a piece of cardboard, one with a
diameter of 4 inches and one with a diameter of 1 inch.
Tape the larger circle firmly to a piece of paper. Poke a pencil
point through the smaller circle, close to the edge. Roll the small
circle around the outside of the large one. The pencil will trace
out the path of a moon circling its planet. This kind of curve is
called an epicycloid. To see the path of the planet around the
sun, poke the pencil through the center of the small circle (the
planet), and roll the small circle around the large one (the sun).
B
A
C
D
J
E
F
G
H
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-610-6
28
© Glencoe/McGraw-Hill 0 Glencoe Geometry
Find x to the nearest tenth. Assume that segments that appear to be tangent are
tangent.
1. 2. 3.
4. 5.
6. 7.
8. 9.
10. CONSTRUCTION An arch over an apartment entrance is
3 feet high and 9 feet wide. Find the radius of the circle
containing the arc of the arch.9 ft
3 ft
20
x x 2 6
20
25
x
6
x x 2 3
6
5
15
x
14
1715
x
3
8
10
x
7
21
20
x4
98
x
11 11
5
x
Practice
Special Segments in a Circle
NAME ______________________________________________ DATE ____________ PERIOD _____
10-710-7
29
© Glencoe/McGraw-Hill Glencoe Geometry
The Nine-Point Circle
The figure below illustrates a surprising fact about triangles and circles.
Given any n ABC, there is a circle that contains all of the following nine
points:
(1) the midpoints K, L, and M of the sides of n ABC
(2) the points X, Y, and Z, where AwXw, BwYw, and CwZw are the altitudes of n ABC
(3) the points R, S, and T which are the midpoints of the segments AwHw, BwHw,
and CwHw that join the vertices of n ABC to the point H where the lines
containing the altitudes intersect.
1. On a separate sheet of paper, draw an obtuse triangle ABC. Use your
straightedge and compass to construct the circle passing through the
midpoints of the sides. Be careful to make your construction as accurate
as possible. Does your circle contain the other six points described above?
2. In the figure you constructed for Exercise 1, draw RwKw, SwLw, and TwMw. What
do you observe?
A
B
M
S
X
K
T
LY
H O
Z
R
C
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-710-7
30
© Glencoe/McGraw-Hill Glencoe Geometry
Write an equation for each circle.
1. center at origin, r 5 7 2. center at (0, 0), d 5 18
3. center at (27, 11), r 5 8 4. center at (12, 29), d 5 22
5. center at (26, 24), r 5 Ï5w 6. center at (3, 0), d 5 28
7. a circle with center at (25, 3) and a radius with endpoint (2, 3)
8. a circle whose diameter has endpoints (4, 6) and (22, 6)
Graph each equation.
9. x21 y2
5 4 10. (x 1 3)21 ( y 2 3)2
5 9
11. EARTHQUAKES When an earthquake strikes, it releases seismic waves that travel inconcentric circles from the epicenter of the earthquake. Seismograph stations monitorseismic activity and record the intensity and duration of earthquakes. Suppose a stationdetermines that the epicenter of an earthquake is located about 50 kilometers from thestation. If the station is located at the origin, write an equation for the circle thatrepresents a possible epicenter of the earthquake.
x
y
O
x
y
O
Practice
Equations of Circles
NAME ______________________________________________ DATE ____________ PERIOD _____
10-810-8
31
© Glencoe/McGraw-Hill Glencoe Geometry
Equations of Circles and Tangents
Recall that the circle whose radius is r and whose
center has coordinates (h, k) is the graph of
(x 2 h)21 (y 2 k)2
5 r2. You can use this idea and
what you know about circles and tangents to find
an equation of the circle that has a given center
and is tangent to a given line.
Use the following steps to find an equation for the circle that has cen-
ter C(22, 3) and is tangent to the graph y 5 2x 2 3. Refer to the figure.
1. State the slope of the line ø that has equation y 5 2x 2 3.
2. Suppose (C with center C(22, 3) is tangent to line ø at point P. What is
the slope of radius CwPw?
3. Find an equation for the line that contains CwPw.
4. Use your equation from Exercise 3 and the equation y 5 2x 2 3. At what
point do the lines for these equations intersect? What are its coordinates?
5. Find the measure of radius CwPw.
6. Use the coordinate pair C(22, 3) and your answer for Exercise 5 to write
an equation for (C.
Px
y
O
C(22, 3)
y 5 2x 2 3
,
Enrichment
NAME ______________________________________________ DATE ____________ PERIOD _____
10-810-8
32
Geometry vocabulary– circles NAME _____________________________
Period ______ Date _______
Name the following from the drawing with circle W.
B
F
A • W C
G
J D
E
H
_________1. the center of the circle
_________2. a radius
_________3. a diameter
_________4. a chord
_________5. a secant segment
_________6. a tangent segment
_________7. a minor arc
_________8. a major arc
_________9. a semi-circle
_________10. a central angle
_________11. an inscribed angle
_________12. a 90 ° angle
_________13. a point of tangency
33
Geometry
Name: Date:
Instructions: Complete the word search puzzle. Use the clues to help you identify the words.
Copyright © The McGraw-Hill Companies, Inc.
Clues
1. An arc that measures 180. 2. The distance around a circle. 3. In a circle, any segment with endpoints that are the center of the circle and a point on the
circle. 4. In a circle, a chord that passes through the center of the circle. 5. A polygon is _____ in a circle if each of its vertices lie on the circle. 6. A line in the plane of a circle that intersects the circle in exactly one point. 7. An irrational number represented by the ratio of the circumference of a circle to the diameter
of the circle. 8. The locus of all points in a plane equidistant from a given point called the center.
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Geometry
Copyright © The McGraw-Hill Companies, Inc.
9. _____ arcs − Arcs of the same circle or congruent circles that have the same measure. 10. Any line that intersects a circle in exactly two points. 11. For a given circle, a segment with endpoints that are on the circle. 12. An arc with a measure less than 180. 13. An __________ angle has its vertex on the circle and its sides go through the interior of the
circle 14. A circle is _____ about a polygon if the circle contains all the vertices of the polygon. 15. An arc with a measure greater than 180. 16. A part of a circle that is defined by two endpoints. 17. point of _____ − For a line that intersects a circle in only one point, the point at which they
intersect. 18. _____ angle − An angle that intersects a circle in two points and has its vertex at the center of
the circle.
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Gra
phic O
rganizer
by
Dale G
raham a
nd
Linda M
eyer
Thom
as C
ount
y
Cent
ral High
Sch
ool
Thom
asville, Ga.
36
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