ANSWER
\(400 \: {in}^{2}\)
EXPLANATION
The figure is made up of a parallelogram and a right angle triangle.
The area of the parallelogram is
\(= base \times height\)
The base of the parallelogram is 20 inches.
The height of the parallelogram is 16 inches.
The area of the parallelogram is
\(= 20 \times 16 \: i {n}^{2}\)
\(=320 \: i {n}^{2}\)
The area of the triangle is
\(= \frac{1}{2} \times base \times height\)
The base of the parallelogram is also 20 inches because opposite sides of a parallelogram are equal in length.
This implies that the area of the triangle is
\(= \frac{1}{2} \times 20 \times 8 \: {in}^{2}\)
\(= 10 \times 8 \: {in}^{2}\)
\(= 80 {in}^{2}\)
We add the two areas to get the area of the figure.
\(= 320 + 80 \: {in}^{2}\)
\(= 400 \: {in}^{2}\)
