Solving Proportions

Front

What is a proportion?

Back

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

Front

How do you determine if two ratios form a proportion?

Back

Two ratios form a proportion if the cross products are equal.

Front

What is the cross product of the ratios a/b and c/d?

Back

The cross product is ad and bc. If ad = bc, then a/b = c/d.

Front

If 2/3 = x/9, how do you solve for x?

Back

Cross multiply: 2 * 9 = 3 * x, so x = 6.

Front

What does it mean if two quantities are proportional?

Back

It means that as one quantity increases, the other quantity increases at a constant rate.

Front

If you can run 4 laps in 10 minutes, what is your rate in laps per minute?

Back

Your rate is 0.4 laps per minute.

Front

If your friend runs 6 laps in 15 minutes, what is their rate in laps per minute?

Back

Their rate is 0.4 laps per minute.

Front

Do the rates 0.4 laps/minute and 0.4 laps/minute form a proportion?

Back

Yes, they are equal, so they form a proportion.

Front

Solve for x: 3/4 = x/16

Back

Cross multiply: 3 * 16 = 4 * x, so x = 12.

Front

What is the first step in solving a proportion?

Back

Identify the two ratios and set them equal to each other.