Question

To the nearest whole number, what is the surface area of a sphere with a volume of 140 cm3?

880 cm2
130 cm2
339 cm2
420 cm2

Answer 1

The answer should be 130 cm2

Answer 2

Answer:
`130\ cm^2`

Explanation:

We know that the volume of sphere is given by :-

`\text{Volume}=(4)/(3)\pi r^3`, where r is radius of the sphere.

Given: Volume of sphere =
`140\ cm^3`

i.e.
`(4)/(3)\pi r^3=140\\\\\Rightarrow\pi r^3=(3)/(4)*140\\\\\Rightarrow r^3=(105)/(\pi)=33.422538\approx33.42\\\\\Rightarrow\ r=(33.42)^(1/3)\approx3.22`

Now, the surface area of a sphere is given by :-

`S.A.=4\pi r^2\\\\\Rightarrow\ S.A.=4(3.14)(3)^2=130.22710\approx130\ cm^2`