Utilities
direct/inverse proportion
Solve direct and inverse proportion problems by entering three values — the tool calculates the fourth automatically. Used for recipes, time estimates, unit conversions, proportional prices, and math exercises.
A recipe: 2 cups of flour yield 12 units — how many with 5 cups?
Using direct rule of three with A=2, B=12, and C=5, the result X is 30 units.
3 painters finish a house in 8 days — what about 4 painters?
Using inverse rule of three with A=3, B=8, and C=4, the result X is 6 days.
Checking ingredient proportions when doubling a recipe
Enter the original quantity, the original yield, and the new desired quantity to find the new proportional yield.
In direct proportion, when one quantity increases, the other also increases (e.g., more hours worked, more pay). In inverse proportion, when one increases, the other decreases (e.g., more workers, less time needed).
Yes. The tool is ideal for helping with math exercises in middle and high school.
Yes, in addition to the result, the calculator displays the proportion steps to help you understand.