# 4: Ratios & Proportionality

**A Ratio is a comparison of two quantities. **

**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.**

**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

Divide the fraction to find the unit rate.

- Lesson 4.2 Notes
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Video on Constant Rate of Change or proportionality

Video Find k from a table. Note: they use "r" instead of k.

WATCH THIS VIDEO: Click here

Practice HERE finding the constant of proportionality

- Lesson 4.3 notes
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Video on write an equation from a table

Practice writing an equation from a table

Video if a graph is proportional find k and the equation

Practice finding constant of proportionality, (k), in a graph