2. Section 8.1 Ratio and Proportion
Chapter 8 Similarity
Section 8.1
Ratio and Proportion

3. All Fractions are ratios

4. Example
3(15) = 5(9)
Example

6. 4 qts in gal
1000 mg in a g
16 oz in a 1 lb
3 ft in a 1 yd

7. 12 in. in a ft
24 hours in a day
100 cm in a m
1760 yds in a mi

9. To Solve a Proportion Cross Multiply
24x = 6(9)
24x = 54
6y = 9(4)
6y = 36
24m = 17(120)
24m = 2040

10. To Solve a Proportion Cross Multiply
6(x + 3) = 8x
6x + 18 = 8x
18 = 2x
9 = x
4(y – 4) = 3(y + 3)
4y – 16 = 3y + 9
y = 25
5y = 3(2y – 7)
5y = 6y – 21
-y = - 21
y = 21

11. 2(20) = 5x
40 = 5x
8 = x

12. 3x = 9(4)
3x = 36
x = 12

13. 8x = 5(44)
8x = 220

14. Your ratio of inches to total length in feet
Write a Proportion
Your ratio of inches to total length in feet
The given ratio
16x = 560
x = 35
Your model is 35 inches long

15. Your ratio of inches to total length in feet
Write a Proportion
Your ratio of inches to total length in feet
The given ratio
x = 80
The actual sub is 80 feet tall

16. HW #10 Pg , 16, 20, 24, 28, 32, 36, 40, 44-47, 51-58, 62-66, Even