Can you me with this math problem

This question is nasty. It sounds like you should be finding area of the figure you see. I'll do that first, although I don't think it's the right answer. (But it might be).

Area Trapezoid = (b1 + b2) * h / 2
b1 = 8
b2 = 12
h = 5
Area Trapezoid = (8 + 12 ) * 5 / 2
Area Trapezoid = 20 * 5/2
Area = 50 square feet.

The problem is that no lumber yard will cut that for you without charging you. The practical answer is 12 * 5  = 60 square feet is what you will have to buy. Then you cut out the triangles for yourself.