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 terms and then solve for the variable.

Front

If a/b = c/d, what is the cross-multiplication method?

Back

The cross-multiplication method states that a * d = b * c.

Front

What is the unit rate?

Back

The unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit.

Front

How do you find the unit rate from a ratio?

Back

To find the unit rate, divide the first quantity by the second quantity.

Front

If a car travels 120 miles in 3 hours, what is the speed in miles per hour?

Back

The speed is 40 miles per hour (120 miles ÷ 3 hours).

Front

What is the formula for finding the cost per item?

Back

Cost per item = Total cost ÷ Number of items.

Front

If 50 apples cost $25, what is the cost of 1 apple?

Back

The cost of 1 apple is $0.50 ($25 ÷ 50 apples).

Front

If there are 5 ice cream cones for every 3 brownies, how do you find the number of cones sold if 24 brownies are sold?

Back

Set up a proportion: 5 cones/3 brownies = x cones/24 brownies, then solve for x.

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions state that two ratios are equal.