Sasindran wrote:

A cylinder resting on its curved surface is half full with volume of water as 462cu.m. What is the diameter of the cylinder if the height of the water is 3m when the cylinder is resting on its circular base?

A. 7

B. 7*(2)^0.5

C. 14*(2)^0.5

D. 14

E. 28

Since we are given that the volume of the water is 462 m^3 and the height of the water is 3 m, if we let r = radius of the base of the cylinder, the volume of the water can be equated as follows:

462 = π x r^2 x 3

154/π = r^2

49 = r^2

r = 7

Since the radius = 7, the diameter = 14.

Note that the height of the water in the cylinder can be confusing. Yes, the actual height of the cylinder is 6 feet, but the volume of water is 462 cu. m.when the cylinder is half full. Thus, we use 3 feet for the height of the cylinder for the given volume. We could use 6 feet for the height of the cylinder, but we would have to double the given volume in order to get the correct answer.

Answer: D

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