Page 76 - Basic College Mathematics with Early Integers

SE CT I O N 1. 6 I MULTIPLYING WHOLE NUMBERS AND AREA 53

Example 10 Finding the Area of a State PRACTICE 10
The state of Wyoming is in
The state of Colorado is in the shape of a rectangle whose length is 380 miles and
the shape of a rectangle whose
whose width is 280 miles. Find its area.
length is 360 miles and whose
Solution: The area of a rectangle is the product of its length and its width. width is 280 miles. Find its area.
#
Area = length width
Fort Collins
= (380 miles)(280 miles)
Boulder 76
= 106,400 square miles Denver
70
70
Colorado
Springs
Pueblo
Colorado
Colorado
25

The area of Colorado is 106,400 square miles.
Work Practice 10

Objective Solving Problems by Multiplying

There are several words or phrases that indicate the operation of multiplication.
Some of these are as follows:

Multiplication

Key Words or Phrases Examples Symbols
#
multiply multiply 5 by 7 5 7
#
product the product of 3 and 2 3 2
#
times 10 times 13 10 13

Many key words or phrases describing real-life problems that suggest addition
might be better solved by multiplication instead. For example, to find the total cost
of 8 shirts, each selling for $27, we can either add
27 + 27 + 27 + 27 + 27 + 27 + 27 + 27
or we can multiply 8(27).

Example 11 Finding DVD Space PRACTICE 11
A digital video disc (DVD) can hold about 4800 megabytes (MB) of information. A particular computer printer
How many megabytes can 12 DVDs hold? can print 16 pages per minute
in color. How many pages can
Solution: Twelve DVDs will hold 12 * 4800 megabytes. it print in 45 minutes?

In Words Translate to Numbers
megabytes per disc : 4800
* DVDs : * 12
9600
48000
total megabytes 57,600
Twelve DVDs will hold 57,600 megabytes.
Answers
Work Practice 11 10. 100,800 sq mi 11. 720 pages