SOLUTION: What is the surface area of a solid prism of length 15cm, the cross-section of the prism is a semi-circle of radius 4cm?

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Question 697474: What is the surface area of a solid prism of length 15cm, the cross-section of the prism is a semi-circle of radius 4cm?
Answer by Simnepi(216) About Me  (Show Source):
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the area of the cylinder's ends are given by
Area = pi X radius^2
A = pi X 4^2 = 50.265cm^2 to 3 decimal places
Therefore their area is 50.265 cm^2 each, which totals 100.53 cm^2
The area of the curved surface of the cylinder is found by finding the circumference of the one end of the cylinder and multiplying this by the length (imagine rolling up a piece of paper to make a hollow tube)
Circumference = pi X diameter
C = pi X 8 = 25.133 to 3 decimal places
So the curved area is
Area = 25.133 X 15 = 376.995 cm^2
The total surface area is therefore
100.53 + 376.995 = 477.525 cm^2