A cylindrical bucket of height 36 cm and radius 21 cm is filled with sand. The bucket is emptied on the ground and a conical heap of sand is formed, the height of the heap being 12 cm. The radius of the heap at the base is :	Options:  A) 63 cm  B) 53 cm  C) 56 cm  D) 66 cm  E) None of these
Volume of the bucket = volume of the sand emptied   Volume of sand = π(21)2 × 36   Let r be the radius of the conical heap.   Then, 1⁄3πr2 × 12 = π(21)2 × 36   or r2 = (21)2 × 9 or r = 21 × 3 = 63   63 cmnswer 63 cm
<result>A</result>
A cylindrical bucket of height 36 cm and radius 21 cm is filled with sand. The bucket is emptied on the ground and a conical heap of sand is formed, the height of the heap being 12 cm. The radius of the heap at the base is :