Solve A:B = C:? proportions.
Solves proportions of the form A:B = C:?. Cross-multiply: ? = (B × C) / A.
Common in scaling recipes, mixing ratios, and comparing proportions.
Ratios and fractions describe the same underlying relationship in different notation, which is why any ratio problem can also be solved by setting up an equivalent fraction equation — pick whichever form is more intuitive for the situation.
3:4 = 9:? → ? = 4 × 9 / 3 = 12.
A ratio compares two quantities (3:4); a fraction expresses one over another (3/4). Same math.
Yes — for double batch of any ingredient with a 3:4 ratio, keep both sides scaled proportionally.
Divide both sides by their greatest common divisor, exactly like reducing a fraction — 8:12 simplifies to 2:3 by dividing both by 4.