CIRCUMFERENCECIRCUMFERENCE ANDAND CIRCLECIRCLE

Circumference is a line whose points Circumference is a line whose points are equidistant to the centerare equidistant to the center

Circle is a portion of plane or area in Circle is a portion of plane or area in a circumferencea circumference

THE CIRCUMFERENCE

A circumference is a closed flat curved where all its points are equidistant from the fixed centre pointThe flat surface outlined by the circumference is called a circle

ElementsElements of a of a circumferencecircumference

Diameter. The straight line that goes through the center of the circumference and intersect it at two points

Radius. It is the segment that connects the center of the circumference to any other point

Secant. It is a straight line that intersects a circumference at two points

Tangent. It is a straight line that crossed the circumference at only the point known as tangent point

Arc. It is the fragment of the circumference between any two points

Chord. It is the segment that connects any two points of the circumference

DiameterRad

ius

Secant

Tangent

Arc

Chord

The radius of a circle is the distance from the center of the circle to the outside edge.

RADIUS

THE DIAMETER

The diameter of a circle is the longest distance across a circle.  (The diameter cuts through the center of the circle.  This is what makes it the longest distance.)

PERIMETER OF A CIRCUMFERENCE

The perimeter is the distance around the outer edge.

Circumference =

where r = the radius of the circleand pi = 3.141592...

A chord of a circle is a line segment that connects one point on the edge of the circle with another point on the circle.(The diameter is also a chord: it's just the longest possible chord of a circle)

An arc of a circle is a segment of the circumference of the circle.

ANGLES

Two rays that share the same endpoint form an angle.

The point where the rays intersect is called the vertex of the angle.

The two rays are called the sides of the angle.

ANGLE

We usually specify an angle using We usually specify an angle using

Greek letters like these Greek letters like these αα, , ββ, , γγ We can also specify an angle with We can also specify an angle with

the letters of its rects adding the the letters of its rects adding the symbol above them : rssymbol above them : rs

αα

r

s

We measure the size of an angle using We measure the size of an angle using degreesdegrees. .

ACUTE < 90ºACUTE < 90º

RIGHT= 90ºRIGHT= 90º

OBTUSE > 90ºOBTUSE > 90º FLAT = 180ºFLAT = 180º

FULL= 360ºFULL= 360º

CLASIFICATION BYMEASUREMENT

Measuring Angles

Complementary Complementary Angles: Angles:

Two angles are Two angles are called called complementary complementary angles if the sum angles if the sum of their degree of their degree measurements are measurements are equals 90 degrees.equals 90 degrees.

º

PAIRS OF ANGLES

An angle bisector is a ray An angle bisector is a ray that divides an angle into that divides an angle into two equal angles.two equal angles.

ANGLE BISECTOR

What kind of shape does have this pizza?

What would it be this portion of pizza in Geometry?