Triangle Angles

What is an angel?…I mean ANGLE!

Two rays with a common endpoint form an angle

Supplementary & Complimentary Angles

Two angles are supplementary if they add up to 180° - forming a straight line

Two angles are complimentary if they add up to 90°

Exterior and Interior Angles Interior angles are inside of the shape Exterior angles are formed when a line

of a shape is extended

The exterior and interior angle in the picture are an example of angles.

Complimentary

Supplementary

94%

6%

1. Complimentary2. Supplementary

Pop Quiz: A triangle has sides and angles.

Two

Three Fo

ur Fi

ve

6%0%

6%

89%

1. Two 2. Three 3. Four4. Five

Pop Quiz: The three interior angles of a triangle add up to how many degrees?

90° 180°

360°

17%11%

72%1. 90°2. 180°3. 360°

Types of Angles

1. Right AngleAn angle formed by perpendicular lines, line segments or rays with a measure of exactly 90°

2. Acute angleAn angle that has a measure greater than 0° and less than 90°

3. Obtuse angleAn angle whose measure is greater than 90° and less than 180°

The following is a(n) angle.

Right

Obtuse Acu

te

0% 0%

100%

1. Right2. Obtuse3. Acute

When painting, a ladder would be set to form a(n) angle with the ground.

Right

Obtuse Acu

te

19%

56%

25%

1. Right2. Obtuse3. Acute

Naming Triangles Using Angles

1. Right triangle A triangle with one right angle

2. Obtuse triangle

A triangle that has one obtuse angle

3. Acute triangleA triangle in which all three angles are

acute

Classify the triangle based on its angle measures.

Right T

riangle

Obtuse Tria

ngl...

Acute Tria

ngle

95%

5%0%

1. Right Triangle2. Obtuse Triangle3. Acute Triangle

An obtuse triangle has one angle with a measure greater than 90° and two angles that are less than 90°

True Fa

lse

43%

57%

1. True2. False

In a right triangle, the two acute angles are…

Complimentary

Supplementary

22%

78%1. Complimentary2. Supplementary

Classifying triangles by side lengths

1. Scalene triangle

A triangle with no congruent sides

or angles

2. Isosceles triangle

A triangle with two congruent sides

and angles

3. Equilateral / Equiangular

triangle

A triangle with three congruent sides and angles

Classify the triangle.

Scalene

Isosce

les

Equila

teral

0%

95%

5%

1. Scalene2. Isosceles3. Equilateral

Classify the triangle.

Acute Iso

scele...

Obtuse Iso

scel...

Acute Sc

alene

Obtuse Scalene

19%

38%

19%

25%

1. Acute Isosceles2. Obtuse

Isosceles3. Acute Scalene4. Obtuse Scalene

Classify the triangle.

Right S

calene

Right Is

oscele...

Acute Iso

scele...

Obtuse Iso

scel...

20%

0%0%

80%1. Right Scalene2. Right Isosceles3. Acute Isosceles4. Obtuse Isosceles