🛠️ ToolsBRFree, fast tools in Portuguese — no sign-up required.

About this tool

Direct and inverse proportions.

How we calculate: Proporção direta (x = b·c/a) ou inversa (x = a·b/c).

🗓️ Values updated in Janeiro de 2026. Informational result, with no fiscal or official value.

➗ Rule of Three

Solve direct and inverse proportions quickly.

📖 How to use this tool

▾
  1. Fill in the three known values.
  2. Choose direct or inverse proportion.
  3. The value of X is calculated automatically.

🔗 Related tools in Utilities