Need answers for a b and c, please help

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.

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?

What is the area of this parallelogram? 434.28 cm2 263.67 cm2 527.34 cm2 217.14 cm2