HELP

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 brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Having a hard time understanding this question (see attachment).