If the surface area of a sphere is 1386 cm2, then find the radius of the sphere.
Answer & explanation
Correct answer: option 2
We know that,
Surface area of sphere = 4πr2
Given,
Surface area of sphere = 1,386 cm2
= 1,386 cm2 = 4 × \(\frac{22}{7}\) × r2
= (1,386 × 7) × \(\frac{1}{4 × 22}\) = r2
= (63 × 7) × \(\frac{1}{4}\) = r2
= \(\frac{441}{4}\) = r2
r = \(\frac{21}{2}\)
r = 10.5 cm