Enter the lengths m, n, and c of a right angle triangle into the calculator to determine the legs a and b.

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## Leg Rule Formula

The following formulas are used to calculate the legs a and b, given the hypotenuse (c) and distances n and m in the diagram below.

a = sqrt (m*c)

b = sqrt (n*c)

## What is the leg rule?

**Definition: **

The leg rule is a rule or set of formulas used in the geometry of a triangle that relates the lengths of two of the sides of the right angle to the projected lengths below them, such as shown in the diagram above.

## How to calculate legs of a triangle?

**Example Problem: **

The following example outlines the steps and information needed to calculate the lengths of the legs of a right-angle triangle.

First, determine the length of the hypotenuse. For this example, the hypotenuse has a total length of 8.

Next, determine the length m in the diagram above. This is the project portion of leg a. In this case, the value is 5.

Next, determine the length of n in the diagram above. This is the project portion of leg b. In this case, the length would be 3.

Finally, calculate the legs a and b using the formula above:

a = sqrt (8*5)

b = sqrt (8*3)

a = 6.322

b = 4.898