The vertical distance between a crest and a trough is 52 cm and 20 waves pass the boat in 30 seconds. 1. The amplitude of a wave is the maximum displacement of a point of a wave from its rest ...

In other words, it is the length of one complete cycle of a wave, measured from one crest (the highest point) to the next crest or from one trough (the lowest point) to the next trough.