# Lesson 2 Ways to Look at Triangles

Let’s sort and analyze triangles.

## Warm-up Number Talk: Sums and Products

Find the value of each expression mentally.

## Activity 1 Triangle Hunt

## Problem 1

From the set of triangle cards, find all the triangles that have each attribute. Record their letter names here.

No right angles | Parallel sides | Perpendicular sides |

The same length for all sides | The same size for all angles | More than one right angle |

More than one obtuse angle | More than one acute angle | Foldable into two equal halves |

## Problem 2

Choose one sentence to complete based on your work.

I noticed that some triangles …

I noticed that all triangles …

I noticed that no triangles …

## Activity 2 The Right Kind of Triangle

Identify all shapes that are right triangles. For each right triangle, mark the right angle with a small square.

Explain why the other shapes are not right triangles.

## Practice Problem

## Problem 1

Which of the triangles are right triangles?

Which of the triangles have an obtuse angle?

Which of the triangles have 3 acute angles?