Page 42 - Basic College Mathematics with Early Integers

S E C T ION 1. 3 I ADDING WHOLE NUMBERS AND PERIMETER 19

Example 5 Find the perimeter of the polygon shown. PRACTICE 5
Find the perimeter of the
3 inches
2 inches polygon shown. (A centimeter
1 inch
is a unit of length in the metric
system.)
4 inches 3 inches
Solution: To find the perimeter (distance around), we add the lengths of the sides.
2 centimeters
2 in. + 3 in. + 1 in. + 3 in. + 4 in. = 13 in.
5 centimeters 8 centimeters
The perimeter is 13 inches.
Work Practice 5 15 centimeters

To make the addition appear simpler, we will often not include units with the
addends. If you do this, make sure units are included in the final answer.

Example 6 Calculating the Perimeter of a Building PRACTICE 6

The largest commercial building in the world A park is in the shape of a
under one roof is the flower auction building of the triangle. Each of the park’s
cooperative VBA in Aalsmeer, Netherlands. The three sides is 647 feet. Find
floor plan is a rectangle that measures 776 meters the perimeter of the park.
by 639 meters. Find the perimeter of this building.
(A meter is a unit of length in the metric system.)
(Source: The Handy Science Answer Book, Visible
Ink Press)

Solution: Recall that opposite sides of a rectangle have the same length. To find
the perimeter of this building, we add the lengths of the sides. The sum of the
lengths of its sides is
776 meters 639
639
776
639 meters 639 meters
+ 776
2830
776 meters
The perimeter of the building is 2830 meters.
Work Practice 6

Objective Solving Problems by Adding

Often, real-life problems occur that can be solved by adding.The first step in solving
any word problem is to understand the problem by reading it carefully.
Descriptions of problems solved through addition may include any of these key
words or phrases:

Addition
Key Words or Phrases Examples Symbols
added to 5 added to 7 7 + 5
plus 0 plus 78 0 + 78
increased by 12 increased by 6 12 + 6
more than 11 more than 25 25 + 11
total the total of 8 and 1 8 + 1
Answers
sum the sum of 4 and 133 4 + 133
5. 30 cm 6. 1941 ft