Question

the hight of a right circular cylinder with lateral surface area 792 cm is 21 cm. find the diameter of its base

Answer 1

given h=21 cm
 l.s.a = 792 cm sq.
2*pi*r*h = 792
2*22/7*r*21 = 792
r  = 792*1/2*7/22*1/21
   = 792*7
       2*22*21
r= 6 cm
diameter = 2r = 12 cm