Question

Describe the formula of 4pie(r)2

Answer 1

Surface area of sphere =
$4\pi {r}^{2}$

radius =7cm
=4×22/7×7×7(7 cancel from 22/7)
=4×22×7
=616cm^2

Answer 2

answer:

let ,we take a sphere of radius =r

put the sphere in hollow cylinder of height =h

let ,

   height of cylinder=diameter of sphere

then,

     h=2r

then,

     SA of sphere=LSA of cylinder

                           =2pie.r.h

                          =2pie.r.(2r)    :(h=2r)

                          =2pie.r^2