What is the speed of a wave trailing off a canoe has a frequency of 8 Hz. and a wavelength measurin?

Speed is cm/sec
Frequency is cycles/sec (Hz means cycles per second.)
Wavelength is cm/cycle.

cm/sec = cm/cycle x cycle/sec Now we do a sanity check. We have cm above the fraction bar and that appears in the answer like we want it. We have cycle below the bar and again above the bar, so that cancels. We have sec below the bar and that appears in the answer like we want it. Now plug in the numbers and multiply all numbers above the bar and then divide by all numbers below the bar.

speed = wavelength x frequency = 10 x 8 = 80 cm/sec

This method is especially important in physics and chemistry where you might have a dozen or so fractions in a single equation.