Math Word Problems Demystified - A Self Teaching Guide

See Figure 20-3.

SinceA¼^12 bh, the equation is 8¼^12 ðxþ 6 Þx:

IMPLEMENTATION: Solve the equation:

8 ¼

1

2

ðxþ 6 Þx

2  8 ¼ 2 

1

2

xðxþ 6 Þ

16 ¼xðxþ 6 Þ

16 ¼x^2 þ 6 x

16 
 16 ¼x^2 þ 6 x
 16

0 ¼x^2 þ 6 x
 16

0 ¼ðxþ 8 Þðx
 2 Þ

xþ 8 ¼ 0 x
 2 ¼ 0

xþ 8 
 8 ¼ 0 
 8 x
 2 þ 2 ¼ 0 þ 2

x¼
 8 x¼ 2

In this case, we ignorex¼
8 since a height cannot be a negative number.

The base isxþ 6 ¼ 2 þ 6 ¼8 inches. Hence the height is 2 inches and the

base is 8 inches.

Fig. 20-3.

244 LESSON 20 Word Problems in Geometry