How to solve a math equation step by step

In the diagram, the ratio of ab to ae is (1/2) . what is the ratio of the length of to the length of ?

The volume of a cube is 8 in to the 3rd power. how long is each side?

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?