Setting Up 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 cross-multiplication method, where you multiply the means and the extremes.

Front

If 16 out of 25 students are boys, how do you find the number of boys in a class of 40?

Back

Set up the proportion: 16/25 = x/40, then cross-multiply and solve for x.

Front

What is the formula to find the equivalent ratio?

Back

The formula is a/b = c/d, where a, b, c, and d are numbers in the ratios.

Front

How can you use proportions to solve real-world problems?

Back

You can use proportions to compare quantities and find unknown values in similar situations.

Front

If a 12-ounce shampoo lasts 16 weeks, how do you find how long an 18-ounce bottle lasts?

Back

Set up the proportion: 12/16 = 18/x, then cross-multiply and solve for x.

Front

What is the relationship between ratios and proportions?

Back

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

Front

How do you determine the number of students who would like pizza if 30 out of 50 do?

Back

Set up the proportion: 30/50 = x/190, then cross-multiply and solve for x.

Front

What is cross-multiplication in proportions?

Back

Cross-multiplication is the process of multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If a car travels 420 miles in 8 hours, how do you find the distance it travels in 12 hours?

Back

Set up the proportion: 420/8 = x/12, then cross-multiply and solve for x.