Question

What is the volume of a hemisphere that has a radius of 80m?

Answer 1

The answer is 134041.3m^3

The volume of a sphere with radius r is:

$V=\frac{4}{3}\pi r^3$

an hesmisphere have half the volume of an sphere, then:

$V_{hemisphere}=\frac{1}{2}\cdot\frac{4}{3}\pi r^3=\frac{2}{3}\pi r^3$

The hemisphere has a diameter of 80m then it's radius is 40m

then

$V=\frac{2}{3}\pi(40m)^3=\frac{128000}{3}\pi\approx134041.3m^3$