Three Four Five Rule Calculator

What is the Three Four Five Rule?

The Three Four Five Rule is a special case of the Pythagorean theorem, where a right triangle has side lengths in the ratio of 3:4:5. This means:

• Side A = 3 units
• Side B = 4 units
• Side C = 5 units

The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides. Mathematically, this is expressed as:

a² + b² = c²

For the Three Four Five Rule:

3² + 4² = 5²

9 + 16 = 25

25 = 25

How to Use This Calculator

1. Enter the side lengths of your triangle (3, 4, and 5 units). If your triangle has different side lengths but is a right triangle, you can enter those values and the calculator will verify if they satisfy the Pythagorean theorem.
2. Click the "Calculate" button.
3. The calculator will display whether the triangle satisfies the Pythagorean theorem (a² + b² = c²).

Applications of the Three Four Five Rule

The Three Four Five Rule is commonly used in:

• Construction and engineering for quick right-angle verification
• Land surveying
• Architecture
• Mathematics education as a fundamental example of the Pythagorean theorem