Basic Mathematics for College Students

22 Chapter 1 Whole Numbers

The Language of Mathematics When you hear the word perimeter,think of

the distance around the “rim” of a flat figure.

EXAMPLE (^8) Endangered Eagles In 1963, there were only 487 nesting
pairs of bald eagles in the lower 48 states. By 2007, the number of nesting pairs had
increased by 9,302. Find the number of nesting pairs of bald eagles in 2007. (Source:
U.S. Fish and Wildlife Service)
Strategy We will carefully read the problem looking for key words or phrases.
WHY Key words and phrases indicate which arithmetic operations should be used
to solve the problem.
Solution
The phrase increased byindicates addition. With that in mind, we translate the
words of the problem to numbers and symbols.

 487  9,302

Use vertical form to perform the addition:

In 2007, the number of nesting pairs of bald eagles in the lower 48 states was 9,789.

Many students find vertical form addition easier if the

number with the larger amount of digits is written on top.

9,302

 487

9,789

The number of

nesting pairs in 2007

increased by9,302.

the number of

nesting pairs in 1963

is equal to

The number of

nesting pairs in 2007

Self Check 8

MAGAZINESIn 2005, the monthly

circulation ofPopular Mechanics

magazine was 1,210,126 copies.

By 2007, the circulation had

increased by 24,199 copies per

month. What was the monthly

circulation of Popular Mechanics

magazine in 2007? (Source:The

World Almanac Book of Facts,

2009)

Now TryProblem 93

5 Find the perimeter of a rectangle and a square.

Figure (a) below is an example of a four-sided figure called a rectangle.Either of the

longer sides of a rectangle is called its lengthand either of the shorter sides is called

its width.Together, the length and width are called the dimensionsof the rectangle.

For any rectangle, opposite sides have the same measure.

When all four of the sides of a rectangle are the same length, we call the rectangle

a square.An example of a square is shown in figure (b).

The distance around a rectangle or a square is called its perimeter.To find the

perimeter of a rectangle, we add the lengths of its four sides.

To find the perimeter of a square, we add the lengths of its four sides.

The perimeter of a square sidesidesideside

The perimeter of a rectanglelengthlengthwidthwidth

Length Side

Side

Side Side

Length

Width Width

A rectangle A square

(a) (b)