1. Chapter 7: Proportions and Similarity

2. 7.1- Proportions
Make a Frayer foldable
7.1 Ratio and Proportion

3. Ratio A comparison of two quantities using division
3 ways to write a ratio:
a to b
a : b
Ex: There are 480 sophomores and 520 juniors in a high school. Find the ratio of juniors to sophomores. Then find the ratio of sophomores to students.

4. Proportion An equation stating that two ratios are equal
Example:
Cross products: means and extremes
a and d = extremes
b and c = means
ad = bc

5. Your Turn: solve these examples

6. Your Turn: solve this example
The ratios of the measures of three angles of a triangle are 5:7:8. Find the angle measures.
A strip of wood molding that is 33 inches long is cut into two pieces whose lengths are in the ratio of 7:4. What are the lengths of the two pieces?