1. 3.4a: Proportions p. 338-345

2. What is a ratio? A ratio is a comparison of two quantities The ratio of a to b can be expressed as: a : b or a/b a/b

3. The total number of students who participate in sports programs at Lincoln High School is 430. The total number of students in the school is 1150. Find the athlete-to-student ratio to the nearest tenth. To find this ratio, divide the number of athletes by the total number of students (as stated above). Find the Student to Athlete ration to the nearest hundredth Example

4. Jerzey has a wallet with: 1-$20 bill 2- $10 bills 1- $5 bill 8-$1 bills 1) What is the ratio of $1 bills to $10 bills? 2) What is the ratio of $10 bills to the total number of bills in the wallet?

5. In a triangle, the ratio of the measures of three sides is 5:10:12, and the perimeter is 135 centimeters. Find the measure of the shortest side of the triangle. A 25 cm B 50 cm C 20 cm D 27 cm Example 5x 10x 12x

6. Example The ratio of the angles in a quadrilateral is 1:2:4:5. Find the measure of the smallest exterior angle.

7. Use Properties of Proportions An equation stating that two ratios are equal is called a __________. Equal, or equivalent, fractions set equal to each other form a _________. i.e. 2 / 3 = 6 / 9 Solve proportions by _________________ ex.

8. Solve

9. 1) Jimmy runs 5.2 km in 30 minutes. At that rate, how far could he run in 45 minutes 2) If Jimmy runs 4 km in 30 minutes, how many hours will it take him to run 1 km

10. Homework