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 terms and then isolate the variable.

Front

If Mike can do 7 push-ups in 15 seconds, how do you find the time for 42 push-ups?

Back

Set up a proportion: 7 push-ups/15 seconds = 42 push-ups/x seconds, then cross-multiply and solve for x.

Front

What is the unit rate?

Back

The unit rate is a comparison of any two units, expressed as a quantity of one unit per one unit of another.

Front

How do you convert a rate to a unit rate?

Back

To convert a rate to a unit rate, divide the numerator by the denominator.

Front

If Ramon travels 20 miles in 20 minutes, how do you find his speed in miles per hour?

Back

Convert minutes to hours (20 minutes = 1/3 hour) and then divide the distance by time: 20 miles / (1/3 hour) = 60 miles per hour.

Front

What is the formula for finding the total cost when buying in bulk?

Back

Total Cost = (Cost per unit) x (Number of units purchased).

Front

How do you set up a proportion to find the cost of 10 pounds of hamburger if 3 pounds cost $6?

Back

Set up the proportion: 3 pounds/$6 = 10 pounds/x dollars, then cross-multiply and solve for x.

Front

What is cross-multiplication in solving proportions?

Back

Cross-multiplication involves multiplying the numerator of one ratio by the denominator of the other ratio and setting the two products equal.

Front

How can you check if two ratios form a proportion?

Back

You can check by cross-multiplying and seeing if the products are equal.