How can you measure the wavelength of a longitude and transverse wave?

Longitidinal waves travel in the form of compressions and rarefractions. the distance beteween 2 consecutive compressions or rarefractions gives the wavelength of the longitudinal wave.

transverse wave travels in the form of a sinousidal wave, it has crests and troughs. the distance between 2 consecutive crests and troughs give the wavelength of a longitudinal wave.