the volume of two hemisphere are in a ratio of 8:27. the ratio of their radii is:

Here is the link given below for the answer similar to your query: 
Use the formulas of hemisphere to get the result. 
https://www.meritnation.com/ask-answer/question/the-volumes-of-two-spheres-are-in-the-ratio-64-27-find/math/3979303  

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