If you know the amplitude of a wave, you know the distance from
the crest of one wave to the crest of the next wave.
the equilibrium of one wave to the equilibrium of the next wave.
the equilibrium of one wave to the crest of the same wave.
the crest of one wave to the trough of the same wave
the crest of one wave to the crest of the next wave.
the equilibrium of one wave to the equilibrium of the next wave.
the equilibrium of one wave to the crest of the same wave.
the crest of one wave to the trough of the same wave