Multiply and Divide to Keep Ratios to a Required Proportion

In this activity, we are going to look at missing values in ratio!

 

Let's look at basic ratio first!

 

This means there are 3 orange circles for every 4 green squares.

If there were 6 orange circles, how many green squares would there be?

 

Every time we have 3 circles we have 4 squares!

To get 6:8 we multiplied both  sides of the ratio by 2!

 

Let's try a question without a diagram.

 

Example

Orange juice to lime juice is in the ratio 2:3.

If there are 14 orange juices, how many lime juices will there be?

 

 

Answer

         Orange juice : Lime juice

 

How did we get to 14?

14 ÷ 2 = 7

So, we must multiply both by 7!

 

​

 

Therefore, we need 21 lime juices!

 

Let's try some questions!