Section 5.1

Ratios and Proportions

Ratios

Commensurable Units: Units that convert to the same units

6 ft to 10 ft

4 in to 15 in

Incommensurable Units: Units that do not convert to the same units.

60 miles to 1 hour

35 miles to 1 gallon

17 baskets made to 20 shots attempted

The ratios 30 to 17 can be expressed three different ways

30:17 or 30 to 17 or

Examples

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2)

a) 20 to 36

5 to 9

b) 24 oz to 52 oz

6 oz to 13 oz

c) 20 oz to 2 lb

20 oz to 2(16 oz)

20 oz to 32 oz

5 oz to 8 oz

d) 2 lb to 20 oz

32 oz to 20 oz

8 oz to 5 oz

Solving Proportions

Means-Extremes Property

Where a and d are the extremes and b and c are the means.

Examples

1) Solve

2) Solve

3) Solve

4) Solve

The Geometric Mean

5) Solve

The Geometric Mean

6) Solve

7) Solve

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18)

20)

24)

Ratios of the sides of the quadrilateral 2:3:4:6