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 unknown 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 ratio of sugar to flour in a recipe if it is given as 10:3?

Back

The ratio means for every 10 parts of sugar, there are 3 parts of flour.

Front

If you have 50 ounces of sugar in a 10:3 ratio, how much flour do you need?

Back

You need 15 ounces of flour.

Front

What is the formula to find the unknown in a proportion?

Back

If a/b = c/x, then x = (b*c)/a.

Front

If a 12-ounce bottle lasts 16 weeks, how long will an 18-ounce bottle last?

Back

An 18-ounce bottle will last 24 weeks.

Front

What is the first step in solving for x in a proportion?

Back

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

Front

What does it mean if two ratios are equivalent?

Back

It means they represent the same relationship between quantities.

Front

How can you check if your solution to a proportion is correct?

Back

You can substitute your solution back into the original proportion to see if both sides are equal.