Beyond Rankers Academy
Building Minds, Not Just Rankers
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Beyond Rankers Academy
Building Minds, Not Just Rankers
Main site →
A ratio compares two quantities. Two ratios that describe the SAME comparison are in proportion. And once you know the cost or amount for ONE, the unitary method finds it for any number.
A ratio compares two amounts. Simplify it exactly like a fraction — divide both sides by their HCF.
12 : 18 → divide both by 6 → 2 : 3
Two ratios are in proportion if cross-multiplying gives the SAME answer both ways.
🔑 The cross-multiply check
For a : b and c : d, they are in proportion if a × d = b × c.
3 : 4 and 9 : 12 → 3×12 = 36 and 4×9 = 36. Equal, so YES, in proportion.
Find the value for ONE unit first, then multiply for however many you need.
12 IMO-style questions on ratio, proportion and the unitary method. 🍀