A cylinder with base radius of 8 cm and height of 2 cm is melted to form a cone of height 6 cm. The radius of the cone will be :
Select:
A) 8 cm B) 9 cm C) 10 cm D) 11 cm E) none

Rationale: sol . let the radius of the cone be r cm . then , 1 / 3 ∏ * r ² * 6 = ∏ * 8 * 8 * 2 ⇔ r ² = [ 8 * 8 * 2 * 3 / 6 ] = 64 ⇔ r = 8 cm . answer a
Answer: A