Mary Beth Briskey

• Two rays that share the same endpoint form an angle.

vertex

side

Angles

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

The two rays are called the sides of the angle.

What is an angle?

How do you measure an angle?

The measure of this angle is…

120°

Type of Angles

A RIGHT angle measures 90°.

An obtuse angle measures from 90° to 180°.

An ACUTE angle measures less than 90°.

A STRAIGHT angle measures 180°

Type of Angles

Complementary angles: angles whose measures add to 90°

Supplementary angles: angles whose measures add to 180°

140 °

40°

58 °

32 °

What type of angle is greater than 90 and less than 180? Obtus

e

If two angles are complementary and one of them measures 40, what is the measure of the second angle?

50A ________ angle measures 90.

right

What is the point where two rays intersect called? vertex

Shapes

Polygons

Definition - a closed figure made by joining line segments, where each line segment intersects exactly two others.

Parallelogram – a four-sided polygon with 2 pairs of parallel sides.

NO

TRIANGLESCharacteristics:

•3-sided•Polygon•Sum of interior angles is 180°

Isosceles Equilateral Right

2 equal sides, 2 equal angles3 equal sides, 3 equal angles One angle is 90°

Congruency

Similarity

Equal angles and equal sides

Equal angles, proportionate sides Similar Symbol

The corresponding congruent sides are marked with small

straight line segments called

hash marks. The corresponding congruent angles are marked with

arcs.

Formulas

AreaMeasures the size of the region enclosed by the figure

Rectangle: A = base x height

Square: A = side ²

Circle: A = П x radius ²

Triangle: A = ½ x base x height

b

h

s

r

h

b

Perimeter

The perimeter of a polygon is the sum of the lengths of all its sides.

The perimeter of the following shapes is…

4

4

44

4

4 5

7

6

4 33

6

4

3

7

3

4+4+4+4+4+4 = 24

6+4+5+6+3+3+4=31

3+7+3+7=20

Circumference

The distance around the outside of a circle.

Formula:

C = 2 x π x radius or C = π x diameter

5

C = 2 X 3.14 X 5 = 31.4

Geometric Designs

A tessellation is a repeated geometric design which covers an

area without gaps or overlaps.

How do you do it????

4. Copy it

Create your own Tessellation!

1. Draw a polygon

2. Reflect, rotate, translate

3. Color/fill

Learn More…..

• Geometry practice problems and lessons:

6th Grade Math Practice

Math.com Homework Help Geometry

•Geometric designs/tessellations:Coolmath4kids.com - Tessellations