If you throw a rock into the water, this will create a wave. The wave would travel outward from the point where the rock hit the water. If propagation velocity is a constant, traveled distance will be velocity multiplied by time. Wavelength is the distance traveled by wave for the time equals to wave period.
Thus, to find out wavelength, we need to multiply propagation velocity by period:
Using the definition of frequency as
we can get standard wave relationship:
The calculator below computes unknown parameters using two known parameters.