2. 1. Ratio: A comparison of 2 numbers by division. i.e.a to b a:ba/b 2. Rate: When a ratio is made up of DIFFERENT units. i.e.3in/4ft$2/5 days UNIT RATE: when the denominator is ONE. i.e.55miles/1 hr$48/1 day

3. 3. Proportion: An equation where 2 ratios are equal. Proportions can be solved by cross multiplying…the product of the extremes = the product of the means. i.e. 2 = 4 510 So solve:6 = 5 12 ?

4. Solve:x = -3 2.5 4 Solve a more complicated problem like: d – 7 = 2d + 1 4 3

5. CONVERSIONS: When converting to a different unit, write a PROPORTION dealing with the 2 units you’re given. For example, suppose you want to change 72 inches into feet… 72 in. = ________ ft. You know 12 inches are in one foot so… 72 in. = 12 in. x feet 1 ft. 72 = 12 x 72/12 = 6 ft.

6. Change 5 ft/hour into inches/min. Do this one step at a time by “cancelling” units: 1. Convert the 5 feet into inches 5 ft ∙ 12 in. = 60 in. 1 hr 1 ft. 1 hr. 2. Now, convert the hours to minutes. 60 in. ∙ 1 hr. = 60 in. 1 hr. 60 min. 60 min.