Pythagorean Theorem Calculator | Find Triangle Side Lengths

Pythagorean Theorem Calculator

Calculate the missing side of a right triangle using the Pythagorean theorem

Find Hypotenuse
Find Side

Calculation Results

Missing Side Length

Pythagorean Formula

a² + b² = c²
Theorem

Triangle Type

Right Triangle

Triangle Visualization

a b c 3 4 5

Geometry Tips

  • The Pythagorean theorem only applies to right triangles
  • The hypotenuse is always the longest side of a right triangle
  • All side lengths must be positive numbers
  • You can use this theorem to verify if a triangle is right-angled
  • The theorem has applications in construction, navigation, and physics

Understanding the Pythagorean Theorem

The Pythagorean theorem is a fundamental principle in geometry that describes the relationship between the sides of a right triangle. It 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.

a² + b² = c²

This theorem is named after the ancient Greek mathematician Pythagoras, who is credited with its discovery, though evidence suggests it was known to Babylonian mathematicians over a thousand years earlier.

Applications of the Pythagorean Theorem

Construction

Ensuring corners are square in buildings and structures

Navigation

Calculating shortest distances between points

Technology

Used in computer graphics and game development

Surveying

Measuring distances in land surveying

How to Use the Pythagorean Theorem

1

Identify the Right Triangle

Ensure you’re working with a triangle that has a 90-degree angle

2

Label the Sides

Identify the hypotenuse (longest side, opposite the right angle) and the two legs

3

Apply the Formula

Use a² + b² = c², where c is the hypotenuse

4

Solve for the Unknown

Rearrange the formula as needed to find the missing side length

Real-World Examples

The Pythagorean theorem has numerous practical applications:

Distance Calculation

Finding the straight-line distance between two points on a map

Construction

Ensuring building foundations are square using the 3-4-5 triangle method

Navigation

Calculating the shortest route between two points

Entertainment

Used in computer graphics to calculate distances and angles

Frequently Asked Questions

Does the Pythagorean theorem work for all triangles?

No, the Pythagorean theorem only applies to right triangles (triangles with one 90-degree angle). For other types of triangles, different formulas like the Law of Cosines must be used.

What is the most common Pythagorean triple?

The most common Pythagorean triple is 3-4-5, where 3² + 4² = 5² (9 + 16 = 25). Other common triples include 5-12-13, 6-8-10, and 7-24-25.

Can the Pythagorean theorem be used in three dimensions?

Yes, the theorem can be extended to three dimensions. The distance between two points (x₁,y₁,z₁) and (x₂,y₂,z₂) in 3D space is √[(x₂-x₁)² + (y₂-y₁)² + (z₂-z₁)²].

How accurate is this calculator?

This calculator provides precise results based on the mathematical formula. The accuracy depends on the precision of your input values. For most practical purposes, it’s perfectly accurate.

What if I get a negative number for a side length?

Side lengths cannot be negative. If you encounter a negative result, check your inputs. The calculator will alert you if the values don’t form a valid right triangle.