# High School Math : Understanding Direct Proportionality

## Example Questions

### Example Question #1 : Understanding Direct Proportionality

Sarah notices her map has a scale of .  She measures between Beaver Falls and Chipmonk Cove.  How far apart are the cities?

Explanation:

is the same as

So to find out the distance between the cities

### Example Question #6 : Other Mathematical Relationships

Sunshine paint is made by mixing three parts yellow paint and one part red paint. How many gallons of yellow paint should be mixed with two quarts of red paint?

(1 gallon = 4 quarts)

Explanation:

First set up the proportion:

x =

Then convert this to gallons:

### Example Question #2 : Understanding Direct Proportionality

If  is directly proportional to , and  when , find a formula for

Explanation:

since  and

Solving for , you get that

Replacing  in the original equation, you get the answer of