Solving proportions, step by step
A proportion is two ratios set equal with one term missing, and finding it is a scale factor away.
The question
1 : 5 = 7 : 35
1 : ▢=7 : 35
1× 7 =7
35÷ 7=5
- Two ratios are equal when both sides were scaled by the same amount. So the first job is to find that amount from the pair you CAN see.
- 1 became 7, so everything was multiplied by 7.
- The blank is on the ratio that was scaled UP from, so it is reached by going back down: 35 ÷ 7 = 5. Not "take the difference away" — a ratio scales, it does not shift.
How it works.
- 01
Two ratios are equal when both sides were scaled by the same amount. So the first job is to find that amount from the pair you CAN see.
- 02
1 became 7, so everything was multiplied by 7.
- 03
The blank is on the ratio that was scaled UP from, so it is reached by going back down: 35 ÷ 7 = 5. Not "take the difference away" — a ratio scales, it does not shift.