Pre-Algebra Demystified

SOLUTION

A¼lw

¼12 ft6ft

¼72 ft^2

The area of a square can be found by using the formula A¼s^2 , where s is the

length of its side.

EXAMPLE

Find the area of the square shown in Fig. 9-9.

SOLUTION

A¼s^2

¼ð8 in.Þ^2

¼64 in:^2

To find the area of a triangle you need to know the measure of its
altitude. Thealtitude of a triangle is the measure of a perpendicular line
from its highest point to its base (the side opposite its highest point). See
Fig. 9-10.

CHAPTER 9 Informal Geometry 171

Fig. 9-8.

Fig. 9-9.