Answer:
Step-by-step explanation:
a). Total surface area of cylinder is defined by sum of curved surface area and surface area of the top and bottom.
Total surface area = 2πrh + 2πr²
Skateboarders use a half pipe structure which are not closed at the ends.
Therefore, curved surface of the half pipe = [tex]\frac{2\pi rh}{2}[/tex]
                                   = πrh
b). If r = 2.5 m and h = 9 m,
Curved surface area of the half pipe = π(2.5)(9)
                               = 70.69 m²
                               ≈ 71 m²
