This worksheet is about keeping pairs of numbers in the same ratio.
If two quantities are in direct proportion, the ratio between corresponding values will always be the same.
a | = | 1 | 2 | 3 | 4 | 5 |
b | = | 1.5 | 3 | 4.5 | 6 | 7.5 |
In this table the ratio between a and b can be found by dividing the value of b by its corresponding value of a.
3 ÷ 2 = 1.5
4.5 ÷ 2 = 1.5
Now we know the ratio between the two values we can find b by multiplying a by 1.5.
For example, if a = 6 then b = 1.5 × 6 = 9
We can also use this ratio to find the value of a if we know what b is.
For example if b = 15, then a = 15 ÷ 1.5 = 10
As we are doing the inverse we divide.