7.1 and 7.2Ratios and Proportions

Ratio

• Comparison of 2 or more things

Expressed in 3 ways

• Quotient using a division sign

• Fraction

• Ratio using a colon ( : )

• Make sure they are in simplest form!

• Always be sure to reduce!

To write the ratio of 2 quantities of different units:

• Express the measures in the same unit (convert bigger unit to smaller unit)

• Write and simplify the ratio

Proportion

• An equation that states two equal ratios

– a:b = c:d “a is to b as c is to d”

d

c

b

a

Means and Extremes

• Extremes: 1st and 4th terms– Ex: a, d

• Means: 2nd and 3rd terms– Ex. b, c

Means/Extremes Property

• Product of the means equals the product of the extremes– Cross-Multiplication Property