1. Section 3.8 Ratios & Rates Made Easy Mr. Beltz & Mr. Sparks

2. Ratio A ratio is a comparison of a number “A” to another number “B” using division. Three ways to express a ratio A to B A : B A B

3. Ways to write Ratio’s PART 1 =.25 or 25% WHOLE 4 or PART : WHOLE 1: 4 = 25%

4. Proportions A proportion is an equation stating that two ratios are equivalent. It can be written in two ways: 4:8 = 8:16 Or 4 = 8 (8 * 8 =64) 8 16 (4 * 16 = 64)

5. Solving for Variables 4 = 8 8 X 4x = 8 * 8 4x = 64 4 4 x = 16

6. Practice: Mental Math 2 = 6 5 X 8 = 4 x 3 3 = X 4 20

7. Using Units Important! Always keep the units lined up! Example: 1 cm : 4 m 12 cm : X m CM 1 cm = 12 cm M 4 m X m

8. Using Units Important! Always keep the units lined up! Example: 1 cm : 4 m 12 cm : X m CM 1 cm = 12 cm M 4 m X m x = 12 * 4 x=48