Rule of Three
Quickly solve the rule of three (if A=B and C=D, find the unknown).
Corresponds to
Result (x)
200
x=
(100 × 20)10
Tips
- • Direct: Cross-multiply (B × C) and divide by the side (A). Commonly used for: Pricing, ingredient weights...
- • Inverse: Horizontally multiply (A × B) and divide by the bottom (C). Commonly used for: Task completion time based on headcount...