If D is the mid .point of side of side BC of a ΔABC, P and Q are two points lying respectively on the sides AB and BC such that DP is parallel to QA. Prove that ar(ΔCQP) = 1/2 ar(ΔABC).
A solid right circular cone of diameter 14 can and height 8 cm is melted to form a hollow sphere.If the external diameter of sphere is 10 cm then find it's internal diameter