Answer: 51 square inches
=======================================================
Explanation:
There are a few ways to do this. One way is to divide the figure as shown in the diagram below. I divided it into a rectangle and a triangle. Find the area of the rectangle and triangle, then add up those areas to get the final answer.
A = area of rectangle
A = length*width
A = 7*6
A = 42
B = area of triangle
B = 0.5*base*height
B = 0.5*(6-3)*(13-7)
B = 0.5*3*6
B = 1.5*6
B = 9
C = total area
C = A+B
C = 42+9
C = 51 square inches
