Question

What is the radius of a sphere with a surface area of 100πcm2?

10 cm
5 cm
25 cm
3 cm

Answer 1

sa=4pir^2

100pi=4pir^2
divide both sides by 4pi
25=r^2
sqrt both sides
5=r
radius=5cm

Answer 2

5 cm

Explanation:

The surface area of a sphere is given by:

`s = 4\pi r^2`

where, r is the radius of the sphere.

It is given that the surface area of a sphere is 100π cm²

⇒ 4πr² = 100π cm²

⇒
`r^2 = (100)/(4) = 25 \\ \Rightarrow r = √(25)=5 cm`

Thus, the radius of a sphere having surface area 100π cm² is 5 cm.