Thread: Calculating Radius of Spheres

Hey, I'm really confused and have no idea. Could someone please complete one of these questions and take me through it. Many thanks

Calculate the Radius of each Sphere:

1. Volume of Sphere -= 250cm^3
2. Vol = 60cm^3
3. Vol = 154cm^3

Originally Posted by carlito1

Hey, I'm really confused and have no idea. Could someone please complete one of these questions and take me through it. Many thanks

Calculate the Radius of each Sphere:

1. Volume of Sphere -= 250cm^3
2. Vol = 60cm^3
3. Vol = 154cm^3

The first thing that you need to know in order to do this problem
is the volume of a sphere of radius r.

The volume of a sphere of radius r is:

V(r) = (4/3) pi r^3.

So if the volume is 250 cm^3, we have:

250 =(4/3) pi r^3,

so:

r^3 = (3/4) 250/pi = 187.5 pi

hence:

r = cbrt(187.5 pi) ~= 8.382 cm

(cbrt denotes the cube root)

The rest are similar.

RonL