RATIOS
A Ratio shows the relative sizes of two or more values.
There are 3 blue squares to 1 yellow square
Ratios can be shown in different ways:
3 : 1 - Using the ":" to separate example values
¾ as a fraction, by dividing one value by the total (3
out of 4 boxes are blue)
0.75 as a decimal
75% as a percentage
Ratios can be shown in different ways:
3 : 1 - Using the ":" to separate example values
¾ as a fraction, by dividing one value by the total (3
out of 4 boxes are blue)
0.75 as a decimal
75% as a percentage
Using Ratios
The trick with ratios is to always multiply the numbers in the ratio by the same value.
Example: 4 : 5 is the same as 4×2 : 5×2 = 8 : 10
The trick with ratios is to always multiply the numbers in the ratio by the same value.
Example: 4 : 5 is the same as 4×2 : 5×2 = 8 : 10
In a table this was:
Allie Mom Length of Foot: 21cm 24cm Height: 134cm 153cm To work out the Ratio she simply divided her Mom's measurements by hers: |
Allie measured her foot and it was 21cm long, and then she measured her
Mother's foot, and it was 24cm long. "I must have big feet, my foot is nearly as long as my Mom's!" But then she thought to measure how tall she and her Mom were, and found she was 134cm tall, and her Mom was 153cm. Allie Mom Ratio (to 3 decimal places) Length of Foot: 21cm 24cm 24/21 = 1.143 Height: 134cm 153cm 153/134 = 1.142 "Oh!" she said, "the Ratios are nearly the same" "So my foot is only as big as it should be for my height, and is not really too big." |