# Lesson 15 Reasoning About Angles (Part 2)

Let’s figure out missing angle measurements.

## Warm-up How Many Do You See: Obtuse Angles

How many angles do you see in the folded paper heart?

## Activity 1 Shaded and Unshaded Angles

Find the measurement of each shaded angle. Show how you know.

## Activity 2 Info Gap: A Whole Bunch of Angles

Your teacher will give you either a problem card or a data card. Do not show or read your card to your partner.

Pause here so your teacher can review your work. Ask your teacher for a new set of cards and repeat the activity, trading roles with your partner.

## Practice Problems

## Problem 1

Find the measure of each labeled angle in the drawing. Assume that:

The angles of the triangles meeting at the point in the middle of the figure are all the same.

The other angles of the triangles all have the same measure.

## Problem 2

In this diagram each angle on the left hand side is the same as the corresponding angle on the right hand side. Find the measure of angles