4: Ratios & Proportionality

A Ratio is a comparison of two quantities.  

Example:  There are 18 daisies and 6 roses.

What is the ratio of daisies to roses:  (we can write this 3 ways)

a) 18 : 6 b)  18 to 6 c) 18 /6

What is the ratio of roses to daisies:

a)  6 : 18 b) 6 to 18 c) 6/18

A Rate is a ratio that compares two quantities measured in different units.

Example:  The car travels 130 miles every 2 hours

What is the Rate:  130 m/2 hr 

A Unit Rate is a rate whose denominator is 1.

How fast does the car travel every hour?:

  130 m / 2 hr = 65 m / 1 hr   or    5/6 mile / 1/3 hr = 2 1/2 mile / 1 hr

Divide the fraction to find the unit rate.

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Practice HERE finding the constant of proportionality