## LESSON: Classifying Triangles

### Objectives/Vocab

## Objectives

- Classify triangles by angles.
- Classify triangles by sides.
- Draw specified triangles using a ruler and a protractor.
- Find unknown angle measures in given triangles.

## Vocabulary

- Triangle
- a three sided figure with three angles. The prefix “tri”means three.

- Acute Triangle
- all three angles are less than 90 degrees.

- Right Triangle
- One angle is equal to 90 degrees and the other two are acute angles.

- Obtuse Triangle
- One angle is greater than 90 degrees and the other two are acute angles.

- Equiangular Triangle
- all three angles are equal

- Scalene Triangle
- all three side lengths are different

- Isosceles Triangle
- two sides lengths are the same and one is different

- Equilateral Triangle
- all three side lengths are the same

- Protractor
- A tool used to measure angles

- Interior angles
- the angles inside a figure