Using the equation of motion:
h = utĀ - 0.5gt², Ā
Ā gĀ is -ve for a rising body, Ā Ā gĀ ā 10 m/s², Ā t = 4s, u = 39.2m/s
Note that in this problem we are neglecting the height of the student.
h = ut - 0.5gt²,
h = 39.2*4 - 0.5*10*4²       Use a calculator
h = 76.8 m
The building is 76.8 m tall.