# Lesson 1:

Proportions and Properties of Similar Figures

## Clarifying the Learning

### Lesson Overview

In this lesson you will review proportions and discover the properties of similar figures. The properties of similarity are very important in real world settings. Constructing scale models require the use of working with similar figures and their properties. In today’s lesson, we are going to look at similar figures—what must be present (and what does not have to be present) for two figures to be similar? Additionally, we are going to discover how to set up and solve proportions that will allow us to solve for missing measures in similar figures.

### Driving Question

What properties must exist for two figures to be similar?

## Defining Success

### Content Standards and Objectives:

After completing this lesson, you should be able to verify experimentally the properties of dilations given by a center and a scale factor.**(M.2HS.STP.1)(CCSS.Math.Content.HSG-SRT.A.1)**

Upon mastering this objective, you should be able to conduct the tasks in the video below:

If you have trouble viewing this video, click here to download.

Given two figures, you should also be able to use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides.**(M.2HS.STP.2)(CCSS.Math.Content.HSG-SRT.A.2)**

Upon mastering this objective, you should be able to conduct the tasks in the video below:

If you have trouble viewing this video, click here to download.