Ratios, Rates, Proportions

Ratios(comparing numbers)

Express the ratio 21 in to 4 ft as a simple fraction. (Don’t forget to change to common units of measurement.)

21 in = 21 in =

4 ft 48 in

Unit Rates(one in the denominator)

A big box of Froot Loops cost $5.49 for 32 oz of cereal. A small box of Froot Loops cost $3.70 for 24 oz of cereal. Compare unit rates to find the better buy.

$5.49 or $3.70

32 oz 24 oz

Proportions(2 equal fractions)

1. My phone company charges $0.10 per min. I am charged $5.75. How minutes was I

yapping on the phone? $0.10 = $5.76

1 min x

2. Carpets come in 2 sizes. The ratio of the 2 rugs

4:1. The big carpet is 10 ft by 14 ft. What are

the dimensions of the little rug? 4 = 10 4 = 14

1 x 1 y

Scale Drawings(just more of the 2 equal fraction

stuff)

On a scale drawing, the scale says

0.25 in:1 ft. What are the dimensions of a room that are 8 ft by 24 ft?

0.25 in = x 0.25 in = y

1 ft 8 ft 1 ft 24

Finding a Scalefor a Model

A building in Tokyo is 256 feet tall.

A model of the building is just 4 in tall.

What is the scale used to make the model

building? 4 in = 1 in

256 ft x

Similar Polygons(angles are congruentsides are proportional

Find the value for x for the similar polygons.

1.

312

x 16

Similar Triangle Stories

A surveyor designs a bridge to go over a lake using similar triangles. Find the length of the bridge.

x

25

53

4

Perimeter and Similar Triangles

There are 2 similar triangles in the ratio of 1:2. If the dimensions of the sides of triangle A are 10 ft, 10 ft, and 25 ft. What is the perimeter of triangle B?

1 = 45 ft

2 x

Area and Similar Triangles

There are 2 similar triangles in the ratio of 1:2. If the base of Triangle A is 10 inches

and the altitude is 8 inches. What is the area of Triangle B.

1 = 40 sq in

4 x