Page 379 - Basic College Mathematics with Early Integers

356 C HAPTE R 5 I RATIO, PROPORTION, AND MEASUREMENT

PRACTICE 6 Example 6 Given the rectangle shown:
Given the triangle shown:
a. Find the ratio of its width to its length.
b. Find the ratio of its length to its perimeter.
10 meters
6 meters
7 feet

8 meters 5 feet
a. Find the ratio of the length
of the shortest side to the Solution:
length of the longest side.
a. The ratio of its width to its length is
b. Find the ratio of the length
of the longest side to the width 5 feet 5
perimeter of the triangle. length = 7 feet = 7

b. Recall that the perimeter of a rectangle is the distance around the rectangle:
7 + 5 + 7 + 5 = 24 feet.The ratio of its length to its perimeter is
length 7 feet 7
= =
perimeter 24 feet 24
Work Practice 6

7
Concept Check Explain why the answer would be incorrect for part a of
Example 6. 5

Objective Writing Rates as Fractions

A special type of ratio is a rate. Rates are used to compare different kinds of quanti-
ties. For example, suppose that a recreational runner can run 3 miles in 33 minutes.
If we write this rate as a fraction, we have
3 miles 1 mile
= In simplest form
33 minutes 11 minutes

When comparing quantities with different units, write the units as part of the
comparison.They do not divide out.

3 inches 1
Same Units: =
PRACTICE 7–8 12 inches 4
2 miles 1 mile
Write each rate as a fraction in Different Units: = Units are still written.
simplest form. 20 minutes 10 minutes
7. $1680 for 8 weeks
8. 236 miles on 12 gallons of
Examples Write each rate as a fraction in simplest form.
gasoline
2160 dollars 180 dollars
7. $2160 for 12 weeks is =
Concept Check Answer
12 weeks 1 week
7
would be the ratio of the rectangle’s 360 miles 45 miles
5 8. 360 miles on 16 gallons of gasoline is = Copyright 2012 Pearson Education, Inc.
length to its width. 16 gallons 2 gallons
Answers Work Practice 7–8
3 5 $210 59 mi
6. a. b. 7. 8.
5 12 1 wk 3 gal