Some one plz me with ese two problems to find the missing angles

Simplify the expression and find the missing terms. the simplest form of has in the numerator and in the denominator.

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

Is the figure congruent? yes or no?