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 first step in solving the proportion 4/x = 2/8?

Back

Cross-multiply to get 4*8 = 2*x.

Front

What is the value of x in the proportion 4/x = 2/8?

Back

x = 8.

Front

If 3/5 = x/20, how do you find x?

Back

Cross-multiply to get 3*20 = 5*x, then solve for x.

Front

What is the solution for x in the equation 3/5 = x/20?

Back

x = 12.

Front

Perry earned $96 for 8 driveways. How much does he earn per driveway?

Back

He earns $12 per driveway.

Front

If Justin types 408 words in 4 minutes, how many words does he type per minute?

Back

He types 102 words per minute.

Front

What is the formula to find the unit rate?

Back

Unit rate = total quantity / total time.