Example 1: Finding the hypotenuse
\(a = 3, b = 4 \rightarrow c^2 = 3^2 + 4^2 = 9 + 16 = 25 \rightarrow c = \sqrt{25} = 5\)
Pythagorean Theorem
Find missing side lengths in right triangles using the Pythagorean theorem
Results
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Theory & Formula
The Pythagorean theorem is a fundamental principle in geometry that relates the sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides.
This theorem only applies to right triangles (triangles with one 90-degree angle). The hypotenuse is always the longest side and is opposite the right angle.
Common Pythagorean Triples
- 3, 4, 5 (and multiples: 6, 8, 10; 9, 12, 15; etc.)
- 5, 12, 13
- 8, 15, 17
- 7, 24, 25
- 9, 40, 41
\(a^2 + b^2 = c^2\)
Worked Examples
Example 2: Finding a leg
\(a = ?, b = 8, c = 10 \rightarrow a^2 = 10^2 - 8^2 = 100 - 64 = 36 \rightarrow a = \sqrt{36} = 6\)