Writing and Solving Proportions

Front

What is a proportion?

Back

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

Front

How do you set up a proportion?

Back

To set up a proportion, you can use the formula a/b = c/d, where a and b are one ratio, and c and d are another ratio.

Front

If 1 pound equals 16 ounces, how many ounces are in 5 pounds?

Back

80 ounces (5 pounds x 16 ounces/pound = 80 ounces).

Front

How do you convert feet to yards?

Back

To convert feet to yards, divide the number of feet by 3, since 1 yard = 3 feet.

Front

What is the formula to find the total points possible if you know the score and percentage?

Back

Total Points = (Score / Percentage) x 100.

Front

If you scored 45 points and that was 80%, how many points was the test out of?

Back

56 points (45 / 0.80 = 56).

Front

What is the first step in solving a proportion?

Back

Cross-multiply the two ratios.

Front

If 3/4 = x/20, what is x?

Back

x = 15 (Cross-multiply: 3 * 20 = 4 * x).

Front

What does it mean to solve for x in a proportion?

Back

It means to find the value of x that makes the two ratios equal.

Front

How can you check if your proportion is correct?

Back

You can check by substituting the value of x back into the proportion to see if both sides are equal.