two term ratio- compares two-quantities measured in the same units.
EXAMPLE: a to b .. a:b
three term ratio- compares three-quantities measured in the same units.
EXAMPLE: a to b to c .. a:b:c
compares two-quantities measured in the different units.
EXAMPLE: 20 miles/ 5 hour
unit rate- a rate which the second term is one.
unit price- a rate used when shopping.
EXAMPLE: $5.99/500 gallons
proportion- s relationship that says that two ratios or two rates are equal.
EXAMPLE: 15 donuts out of 30 donuts are equal to 1 donut out of 2 donuts.