1. 7.1 Ratio and Proportion

2. Ratio
Ratio- compares two numbers by division. Can be written as “a to b, a:b, or
In a ratio, the denominator of the fraction cannot be zero because division by zero is undefined.

3. Example
Write a ratio expressing the slope of l.

4. Example
Given that two points on m are C(–2, 3) and D(6, 5), write a ratio expressing the slope of m.

5. Example
The ratio of the side lengths of a triangle is 4:7:5, and its perimeter is 96 cm. What is the length of the shortest side?

6. Example
The ratio of the angle measures in a triangle is 1:6:13. What is the measure of each angle?

7. Definitions Proportion: an equation stating that two ratios are equal.
Means: b and c values
Extremes: a and d values

8. Cross Products Property

9. Examples
Solve the Proportion. 1) 2) 3) 4)

10. Examples
Solve the Proportion. 5) 6)

11. Properties of Proportions

12. Examples
Given that 18c = 24d, find the ratio of d to c in simplest form.
Given that 16s = 20t, find the ratio t:s in simplest form.

13. Example
Marta is making a scale drawing of her bedroom. Her rectangular room is 12 feet wide and 15 feet long. On the scale drawing, the width of her room is 5 inches. What is the length?