I think I have the right answer but I want to make sure it’s right

Which of the following is the rational exponent expression of 6 root f

You drop a rubber ball off the roof of a 50 meter high building onto a paved parking lot. it bounces back up with every bounce, but not quite all the way back up to you. after the first bounce it bounces back only 80 percent of the distance it was dropped from. the pattern continues, meaning after every bounce it comes up to just 80 percent of the previous maximum height. so if before the first bounce the height is 50 meters, what height does the ball reach after the fifth bounce? round your answer to one decimal place and chose the correct response from the choices below:

Amachine part consists of a half sphere and a cylinder, as shown in the figure. the total volume of the part is π cubic inches.