+
Solving proportions

Solving proportions

Rating:
Rating
(0)
Description:

This lesson will introduce solving proportions by turning them into equations.

(more)
See More

Try Our College Algebra Course. For FREE.

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to over 2,000 colleges and universities.*

Begin Free Trial
No credit card required

25 Sophia partners guarantee credit transfer.

221 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 20 of Sophia’s online courses. More than 2,000 colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Tutorial

Definitions

Ratio: comparison of two numbers, usually written as a fraction

Proportion: two ratios set equal to each other

Variable: a symbol, usually a letter, that takes the place of a value

Numerator: the top or left side of a fraction

Denominator: the bottom or right side of a fraction

Solving Proportions

There are many different ways to solve for a missing number in a proportion. The method we will look at today is turning them into equations. Let's look at this proportion for an example: 3/4 = 6/x. We are looking for the missing value at x.

To do this, we will start by multiplying the first numerator by the second denominator. In this case, my values are 3 and x. 3 time x is 3x.

Now, we will multiply the first denominator by the second numerator. My values are 4 and 6. 4 times 6 is 24.

I will now set these two values equal to each other: 3x = 24.

How do we solve for the x? To find the value of x, we will divide each side of the equation by 3. 3x divided by 3 is just x. 24 divided by 3 is 8.

My answer is x = 8.

If we put 8 back in for x, we will see that our fractions are equal, or proportional.

3/4 = 6/8