Can someone help me out with these problems

This stem-and-leaf plot represents the heights of the students on ralph's basketball team. one student's height is missing from the plot. if the mean height of all the students on the team is 61 inches, what is the missing height? a. 55 in. b. 59 in. c. 61 in. d. 65 in.

21 type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. the solution set of n2 - 14n = -45 is { (separate the solutions with a comma)

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.