A¼
1
2
bh
30 ¼
1
2
ðxþ 7 Þx
30 2 ¼
21
1
1
21
ðxþ 7 Þx
60 ¼x^2 þ 7 x
60 60 ¼x^2 þ 7 x 60
0 ¼x^2 þ 7 x 60
0 ¼ðxþ 12 Þðx 5 Þ
xþ 12 ¼ 0 x 5 ¼ 0
xþ 12 12 ¼ 0 ¼ 0 12 x 5 þ 5 ¼ 0 þ 5
x¼ 12 x¼ 5
The height is 5 feet and the base is 5þ 7 ¼12 feet.
9 : Letx¼the length of the side of the smaller square
and 6x¼the length of the larger square; then
(6xÞ^2 x^2 ¼ 875
36 x^2 x^2 ¼ 875
35 x^2 ¼ 875
351 x^2
351
¼
875
35
x^2 ¼ 25
x¼
ffiffiffiffiffi
25
p
¼5 inches
250 LESSON 20 Word Problems in Geometry