Math Word Problems Demystified - A Self Teaching Guide

x¼ 368

2 x¼ 2  368 ¼ 728

Hence the measures of each of the angles are 36 8 ,72 8 , and 72 8.

EVALUATION: See if the sum of the angles is 180 8.

368 þ 728 þ 728 ¼ 1808

EXAMPLE:If the length of a rectangle is four times its width and the

perimeter of the rectangle is 80 inches, find the measures of its length and

width.

Geometric principle: The perimeter of a rectangle isP¼ 2 lþ 2 w.

SOLUTION:

GOAL: You are being asked to find the length and width of a rectangle.

STRATEGY: Letx¼the width of the rectangle

and 4x¼the length of the rectangle

See Figure 20-2.

Since the formula for the perimeter of a rectangle is P¼ 2 lþ 2 w, the

equation is

2(4x)þ(2x)¼80.

Fig. 20-2.

242 LESSON 20 Word Problems in Geometry