Two spheres m and n have volumes of 250 cm and 750 cubic cm respectively. What is the ratio of their radius

Let's look at the formula for the volume of a sphere:

Volume = (4/3) (pi) (radius) ³.

If you multiply the radius of a sphere by 'anything',

then the volume gets multiplied by (anything) ³.

Going the other direction, if you multiply the volume by

'something', then the radius gets multiplied by ∛ (something).

In this question, the ratio of the volumes is 3.

So the ratio of the radii (radiuses) is ∛3 = about 1.442 (rounded)