Answer:
Formula: nl(b + h) it is derived as well
504 ft²
Step-by-step explanation:
Each vertical face is a rectangle.
Area of each face = length x breadth = lb
For n-sided polygon, area of vertical faces = n x lb = nlb
For horizontal faces:
Observe: you can actually divide that face in 5 right-angled triangle(two edge point & centre form right angled ∆). [For n-sided, that's n right angled ∆]
For 2 such faces, you have 2 x n times of area of 1 ∆.
Area of 2n∆ = 2n( ½ x h x base(length)) = nhl
Total area = area of horizontal surfaces + area of vertical surfaces
Total area = nlb + nhl = nl(b + h)
Total area = 5*9(5 + 6.2) = 504 ft²
