The surface area of a right cone is 55π cm squared. Find the radius if the slant height is 6cm.

Answer 1

S.A. = πr(r + 6)

55π = πr² + 6πr

55 = r² + 6r

r² + 6r - 55 = 0

(r + 11)(r - 5) = 0

r = 5 cm