What frequency of sound has a wavelength of 75cm?

At first you have to convert your wavelength to meters:75 cm = 0.75mthen you need to know the speed of sound - I've found that it is 340.29 m/sand finally,  you can use this equation:λν = c(0.75m) (f) = 340.29f = 340.29 / 0.75f=453.72 Hz