Digits, Grade 8, Volume 1, Homework Helper

### 2-4: Unit Rates and Slope

#### Key Concept

A rate is a ratio that describes how one quantity changes as the other quantity changes.

You can find a unit rate from a graph in the same way that you find slope.

Choose two points on the graph to find the slope. Use the points (0, 2) and (3, 6).

table with 3 rows and 2 columns , row1 column 1 , slope , column 2 equals . fraction changein . y . minuscoordinates , over changein . x . minuscoordinates end fraction , row2 column 1 , , column 2 equals . fraction 6 minus 2 , over 3 minus 0 end fraction , row3 column 1 , , column 2 equals , 4 thirds , end table

The slope of the line is 4 thirds . The slope can be interpreted as a rate or a unit rate.

The plant grew at a rate of fraction 4 in . , over 3weeks end fraction . or , 4 thirds in. per week.

#### Part 1

Example Finding Unit Rates from Graphs

The graph shows the amount of milk used to make a particular cheddar cheese. How many ounces of cheese can you make per gallon of milk?

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