**Introduction to **

**Ratio, Proportion, and **

**Similarity**

Overview for the topic:

- learn how to write and simplify ratios

- learn how to determine whether two ratios are a proportion and how to use proportions to solve problems learn how to determine whether two triangles are similar

**What is a **

**Ratio?**

A *ratio *is the comparison of two numbers using division.

The ratio of *x *to *y *can be written or x:y.

Ratios are usually expressed in simplest form.

**What is a **

**Proportion?**

Since 2/4 and 3/6 are both equal to 1/2, they are equal to each other.

A statement that two ratios are equal is called a *proportion*.

A proportion can be written in one of the following ways:

2/4 =3/6 or 2:4 = 3:6

The first and last numbers in a proportion are called the *extremes*.

The middle numbers are called the *means*.

*Proportion*

**Means-Extremes Property**

In a proportion, the product of the means equals the product of the extremes.

*Proportion*

**Triangle Similarity**

Two figures are similar if you can show that the following two statements are true:

1. Corresponding angles are congruent.

2. Corresponding sides are in proportion.

Examples:

SOURCE: http://www.education.com/study-help/article/ratioproportion-similarity/