Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Math
Proportion Calculator
Find the missing fourth value d in any proportion a/b = c/d when three values are known. Perfect for scaling recipes, converting units, solving map distances, and cross-multiplication problems.
Fill in the required fields to see your result.
Math
Circle Area Calculator
Calculate the area of a circle from its radius using A = πr². The foundational geometry formula for circles, used in everything from pizza sizing to engineering.
Fill in the required fields to see your result.
Key differences
| Proportion Calculator | Circle Area Calculator | |
|---|---|---|
| Category | Math | Math |
| Inputs required | 3 | 1 |
| Result | d | Area (square units) |
| What it does | Find the missing fourth value d in any proportion a/b = c/d when three values are known. Perfect for scaling recipes, converting units, solving map distances, and cross-multiplication problems. | Calculate the area of a circle from its radius using A = πr². The foundational geometry formula for circles, used in everything from pizza sizing to engineering. |