Answer:
(l*w) - ((pi/2)*((l/2)^2)) or (8*10) - ((pi/2)((8/2)^2)) = 80 - 8pi
Explanation:
You find the area of the pool if it was a rectangle (l*w or 8*10)
From that, you subtract the area of the semicircle (pi/2*(l/2)^2 or pi/2*(8/2)^2)
So you get:
(l*w) - ((pi/2)*((l/2)^2)) or (8*10) - ((pi/2)((8/2)^2))
which equals 80 - 8pi