A cone has a circular base, a perpendicular height of 21cm, and a semi-vertical angle of 30degree. calculate the slant height of the cone. find the area of it's base

Answer 1

so the radius is r = 21 cot30° = 21/√3
that makes the
slant height s = 21 sec30° = 42/√3
area = πr^2 + πrs