Question

How to solve for wavelength

Answer 1

There is the formula v = λf,
where v is velocity of the wave, λ (lamda) is wavelength, and f is frequency.

To solve for wavelength (λ), divide both sides by f.
v = λf
v/f = (λf)/f
v/f = λ

Answer 2

wavelength is the distance of one frequency wave peak. If you know the speed and frequency of the wave you can use basic formula for wavelength which is Wavelength= Wave Speed over Frequency