This was a two stage question. Stage 1 was calculating the area of the below shape sans curve. Stage 2 is to calculate the area of the shaded region below.
We are told the curve has a radius of
Note the diagram is not to scale.
So for stage 1, I calculated the area to be $22*15 (height) - 5*7 +1/2 (30+7-22)*15(height) = 407500 $ square units
So I believe if I were to subtract the white area from the diagram above I'd have the area for the shaded region, but I'm stuck in how to determine that area.