Solving Proportions

Solving Proportions

Before I begin with my lesson on proportions, it is important to know what a proportion is.

      

                A proportion is an equation showing that two units, rates, etc are equal.

Proportions are like equations. However, don't get confused! The difference between an equation and a proportion is, proportions show how two things are equal. Equations on the other hand, don't necessarily show two equal things.

Let's look at some examples below.

Example 1

Solve for x

2 =6

3 =x

HOW DO I SOLVE THIS PROBLEM???!!!??

Well, there are many ways to solve this problem. One way is by using cross multiplication, which I will show you how to do.

First, you do 3(6), since you're multiplying the denominator of the first fraction by the numerator of the second fraction in this case. In other proportions, it might be vice verso. The product is 18. Next, you divide 18 by the numerator 2. Your answer is 9. So...

x=9

Let's look at a second problem.

Example 2

Solve for o.

5 = o

6 =30

Using cross multiplication, multiply 5(30), which is 150. Then, divide 150 by 6, and the answer is 25. So....

o=25

               ARE THERE OTHER WAYS TO SOLVING PROPORTIONS?

There are other ways to solving proportions too, such as by using equivalent fractions or ratios. Or, you can convert the fraction into decimals and find equivalent decimals. There are multiple ways to solving proportions, including cross multiplication. However, choose the method that works best for you.

APPLYING PROPORTIONS TO YOUR DAILY LIFE

In real life, you might be using proportions and not even know it! Proportions don't have to appear in your math textbook for you to be using them. Proportions can appear quite differently. A person might have to deal with proportions when baking something like a batch of cookies. For example:

Let's say that a girl called Allison is baking a batch of cookies for her and her 3 friends.

-The recipe calls for 2 quarts of dough, and can make only for 2 people.

           

                                  How would you solve this problem?


Another time proportions might come up is when you're travelling to a country such as your home country, and you need to find the currency rate. Proportions will come up handy in that scenario.

               

As you can see, solving proportions are quite easy. One way is by using cross multiplication, which is a simple and easy method to use. I hope you now understand proportions.