1. The problem statement, all variables and given/known data For part aiii), the mark scheme states "Use of set squares to indicate height". I know what are set squares, but how does it aid to determine the rebound height, h? I thought set squares are to ensure two objects are perpendicular to one another? How does it help in measuring the rebound height, h? Also, for part c), how to explain? Is it because both h and d have the same unit, thus cancel out, giving a constant?