Question

If the height of a right circular cone is increased by 200% and the radius of the base is reduced by 50%, then the volume of the cone:

Accepted Answer

B. Initial Volume $V = \frac{1}{3} \pi r^2 h$. New height $h' = h + 2h = 3h$. New radius $r' = 0.5r$. New Volume $V' = \frac{1}{3} \pi (0.5r)^2 (3h) = \frac{1}{3} \pi (0.25 r^2) (3h) = 0.75 V$. Change in volume = $0.75V - V = -0.25V$, which is a decrease of 25%.

Change in volume of cone

Explanation

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