Answer
A$\triangle$=25
Work Step by Step
1. Use formula for the area of a triangle to solve (A=$\frac{1}{2}$bh) to find the area of all 3 triangles.
2. Use A=lw to find the area of the rectangle
3. subtract the area of all 3 triangles from the area of the rectangle. (combine whole numbers to make mixed fractions, combine mixed fractions to get whole numbers in work below)
a. 8$\times$7-$\frac{1}{2}$$\times$5$\times$1-$\frac{1}{2}$$\times$7$\times$7-$\frac{1}{2}$$\times$ 1$\times$8
b. 56- $\frac{5}{2}$ -$\frac{49}{2}$- $\frac{8}{2}$
c. 56-31=25
