Question

a cone with radius 3cm has a total area 24pi cm^2. Find its height

Answer 1

clearly, the area of the base = 9pi cm^2
so, area of the slant surface=15 pi cm^2
area of slant surface= 1/2 * slant height* perimeter of base
in this case, perimeter of base= 6 pi cm
so, the slant height= 5 cm (after calculation)
radius=3 cm
so, height= 4 cm