Discussion of Question with ID = 039 under Volume-and-Surface-Areas

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Question

What is the volume of a cone generated by rotating a right angled triangle with sides 25, 7 and 24 cm? The rotation is done about the side of length 24 cm.

A

392 π sq. cm.

B

393 π sq. cm.

C

391 π sq. cm.

D

$131{2/3}$ π sq. cm.

Soln.
Ans: a

The radius of the base of the cone r = 7 cm, and height h = 24 cm. The volume is $1/3$π$(r^2 × h)$ = $1/3$π$(7^2 × 24)$ = 392π.


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