rates - compares two quinities measured in different units.
Eg. $1.69 per 100g for purchasing bulk food.
72 beats per minute is a heart rate.
ratios- Compares two quantities measured in the same units.
two term ratios eg. a:b or a to b
three-term ratio eg.a:b:c or a to b to c
proportional reasoning- A reletionship that says that two ratios or two rates are equal.
can be written in fraction form 2km/3h , 6km/9h