Today we’ll discuss one of the simple applications of the Pythagorean theorem: finding the lengths of the edges in a right triangle.
The most common application of the Pythagorean theorem is to use the known lengths of two of the sides of a right triangle to find the length of the third side, using algebra and the formula a² + b² = c².
Problem
In a right triangle, one of the legs (a) measures 4 units, the other leg (b) measures 3 units. Find the length of the hypotenuse, c.
Strategy
This is a straightforward application of the Pythagorean theorem. We know sides a & b, so we simply plug them into the formula:
a² + b² = c²
a= 4, b=3 //given
4² + 3² = c² // simple substitution
16 + 9 = c²
25 = c²
√25 = c
c = 5