Solving Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the two ratios and set the products equal to each other.

Front

If 4 pages take 18 minutes to read, how do you find the time to read 30 pages?

Back

Set up a proportion: 4 pages/18 minutes = 30 pages/x minutes, then cross-multiply and solve for x.

Front

What is the formula to find the unit rate?

Back

The unit rate is found by dividing the quantity by the number of units, e.g., yards per minute.

Front

If a machine produces 21 yards in 7 minutes, how much does it produce in 1 hour?

Back

First find the unit rate: 21 yards/7 minutes = 3 yards/minute. Then multiply by 60 minutes: 3 yards/minute * 60 minutes = 180 yards.

Front

How do you find the weight of one item if you know the total weight and number of items?

Back

Divide the total weight by the number of items.

Front

If 15 bags weigh 45 pounds, how much do 7 bags weigh?

Back

First find the weight of one bag: 45 pounds/15 bags = 3 pounds/bag. Then multiply by 7 bags: 3 pounds/bag * 7 bags = 21 pounds.

Front

What is the relationship between gallons and bottles in a proportion problem?

Back

You can set up a ratio of gallons to bottles and use it to find the unknown quantity.

Front

If 4 bottles hold 8 gallons, how much do 3 bottles hold?

Back

Set up a proportion: 4 bottles/8 gallons = 3 bottles/x gallons, then cross-multiply and solve for x.

Front

How do you calculate the total weight of multiple items?

Back

Multiply the weight of one item by the number of items.