cycle per second ; pulse per second are just example. It could be anything
like feet per second; miles per hour; kilometer per hour. Notice when you do cross multiplication the units of measurement will be divided by itself. Meaning any units of measurement divided by itself will be equal to 1. For example cycle*second / cycle*second = 1.
So in ratio and proportion there is no unit of measurement. Why do you need to acquire this knowledge? You use ratio and proportion to scale up or scale down anything that you can measure. For example Google Map scale is 1 inch = 200 ft. What is the distance if the measurement is 11.75 inches?
Enter the following : 1 inch / 200 feet = 11.75 inches / ? feet
Make sure numerator has the same unit of measurement for example inch and the denominator has the same unit of measurement for example feet.
cycle
second
 = 
cycle
second

pulse
second

= 
pulse
second
