Solution
For this case we can do the following:
A = b*h
Where h = height and b = base
So the total area is :
22ft * 18 ft = 396 ft^2
If we analyze the whitespace area we can see that we have a square and a triangle
The area of the square is given by:
a1 = 5ft* 4ft= 20 ft^2
And the area of the triangle is given by:
a2 = (5*5)/2 = 12.5 ft
Then the final answer for this case would be:
A f= 396 - (20+12.5) ft^2 = 363.5 ft^2