Question

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

Answer 1

The answer should be 130 cm2

Answer 2

Answer: $130\ cm^2$

Step-by-step explanation:

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

$\text{Volume}=\dfrac{4}{3}\pi r^3$, where r is radius of the sphere.

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

i.e. $\dfrac{4}{3}\pi r^3=140\\\\\Rightarrow\pi r^3=\dfrac{3}{4}\times140\\\\\Rightarrow r^3=\dfrac{105}{\pi}=33.422538\approx33.42\\\\\Rightarrow\ r=(33.42)^{1/3}\approx3.22$

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

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