Question

The ratio between the radii of two spheres is 9:2 What is the ratio of their volumes?

Answer 1

There are several important information's already given in the question. Based on those given information's the answer can be easily deduced. 

Ratio of the radii of two spheres = 9 : 2
then
Ratio of the volume of the two spheres = 9^3 : 2^3
                                                               = 729 : 8
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