Question

A spherical ball is divided into two equal halves. If the curved surface area of each half is 56.57cm2,find the radius of the original spherical ball.

Answer 1

Curved surface area of a sphere=4×pi×r²
Csa of half of sphere(or)hemisphere=2×pi×r²
Given CSA of hemisphere=56.57cm²

Radius of hemisphere=radius of complete sphere

Acc to the question
2×pi×r²=56.57
r²=56.57/2×pi
=56.57/6.28
r²=9.007 =9(approx)

r=root of 9 = 3cm

Hence the radius of sphere is equal to 3cm

Answer 2

This should help.
Good luck!