Question

find the radius of a a sphere whose surface area is 154cm²

Answer 1

S.A = 4×pi×r^2
(154×7)/(4×22)=r^2
49/4=r^2
Therefore r = 7/2 = 3.5

Answer 2

The surface area of the sphere = 154 cm²
=> 4πr² = 154
=> r² = 154 × 7/22 × 1/4
=> r² = 12.25
=> r = √12.25
=> r = 3.5 cm

Hope this helps......