3.2 Connecting ratio and proportion
Throughout this week you have looked at various applications of proportional reasoning. Finally, you will look at how notation for ratio and proportion are linked.
Recapping what was discussed at the start of this section, a ratio represents a relationship between two quantities. A proportion represents one quantity in relation to the whole.
For example, a tropical drink uses 150 ml of orange juice and 100 ml of mango juice.
The ratio of orange to mango, in the simplest form, is 3:2, as for every 3 parts of orange juice, 2 parts of mango juice is needed.
Expressed as a fraction, the proportion of orange juice in the drink is
as there are 5 parts in total and 3 of these are orange juice.
Activity 19 Matching ratio and proportion
Allow 10 minutes
For each of the sets of counters displayed, write the ratio and proportion in the box below.
Answer
Ratio of red to blue is 3:1
The proportion of red is
Answer
Ratio of red to blue is 1:2
The proportion of red is
Answer
Ratio of red to blue is 4:5
The proportion of red is
Answer
Ratio of red to blue is 2:3
The proportion of red is
Answer
Ratio of red to blue is 1:1
The proportion of red is
Answer
Ratio of red to blue is 1:3
The proportion of red is
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