Peljsenick Peljsenick 17-08-2016 Mathematics contestada the diameter of the base of a right cone is 6 cm. if the total surface area of the cone is 90π cm^2, what is the length of the slant height? a.) 6.6 cm. b.) 9 cm. c.) 21 cm. d.) 27 cm. could i have the formula to solve this problem?