Question

what is the surface are of a colonial grain storage tank that has a height of 54 meters and a diameter of 18 meters? 1802m^2, 1781m^2, 3110m^2, 1548m^2.. thanks

Answer 1

The tank has the shape of a cone
So, the area of the cone = π r²+ π r s

where r is the radius           
          s is the slant height = √(r²+h²)
          h is the height
given the diameter = 18 m and the height = 54 m
∴ r = 9 m  ,  h = 54 m
∴ s = √(r²+h²) = √(9² + 54²) = 54.745 m
∴ Area = π r²+ π r s
             = π * 9² + π * 9 * 54.745 ≈ 1802.3 m²

The correct answer is the first option 1802 m²