In a right triangle, the sum of the squares of the legs equals the square of the hypotenuse.
Symbols
a,b
legs
c
hypotenuse
Where it comes from
In a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs. It is the basis for computing distances and diagonals.
When to use it
Right triangles; diagonals, distances, heights.
Example
The legs have lengths 3 and 4. Find the hypotenuse.