# Lesson 8 Sort Triangles

• Let’s sort triangles.

## Warm-up Estimation Exploration: Angle Measure

What is the measure of the angle?

Record an estimate that is:

too low

too high

## Activity 1 The Right Fit

1. Find a triangle card that fits in each space on the grid.

2. If you don’t think it is possible to find a triangle that fits certain criteria, explain why not.

all three side lengths are different

exactly two of the side lengths are the same

all three side lengths are the same

has a 90 degree angle

has an angle that is greater than 90 degrees

all three angles are less than 90 degrees

Explanations:

## Problem 1

Sort the triangle cards from the previous activity in a way that makes sense to you. Describe how you sorted the cards.

## Problem 2

Now sort out the triangles with a 90 degree angle. For these triangles, write statements about each category.

1. All of the triangles with a 90 degree angle  …

2. Some of the triangles with a 90 degree angle …

3. None of the triangles with a 90 degree angle  …

## Problem 1

For each description, draw a right triangle with the described side lengths on the grid or explain why there is no such right triangle.

• 2 equal side lengths

• 3 equal side lengths

• 3 different side lengths