Hypotenuse of a Right Triangle in Feet Calculator | Pythagorean Theorem Calculator

Hypotenuse of a Right Triangle in Feet Calculator

Calculate the length of a right triangle’s hypotenuse using the Pythagorean theorem

Hypotenuse Calculator

ft
ft

The Pythagorean Theorem

The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse (c) is equal to the sum of squares of the other two sides (a and b).

c² = a² + b²

c = √(a² + b²)

Where:

  • c is the length of the hypotenuse (in feet)
  • a is the length of the base (in feet)
  • b is the height (in feet)

* A right triangle has one angle that is exactly 90 degrees (a right angle).

Interactive Visualization

This visualization updates as you change the base and height values. The hypotenuse is shown in red.

* Move the sliders to adjust the triangle dimensions and see how the hypotenuse changes.

Practical Applications

Construction

Used for determining diagonal bracing lengths, roof pitches, and ensuring right angles in framing.

Carpentry

Essential for measuring diagonal cuts, calculating stair dimensions, and ensuring square corners.

Land Surveying

Used to measure distances across inaccessible areas and calculate property boundaries.

Engineering

Applied in structural analysis, determining forces in trusses, and designing support systems.

The 3-4-5 Rule

Construction professionals often use the 3-4-5 rule to quickly establish a right angle:

  • Mark a point 3 feet along one wall
  • Mark a point 4 feet along the perpendicular wall
  • If the diagonal between these points is exactly 5 feet, you have a perfect right angle

This is a practical application of the Pythagorean theorem: 3² + 4² = 5²

Frequently Asked Questions

What is the hypotenuse of a right triangle?

The hypotenuse is the longest side of a right triangle, which is always opposite to the right angle (90-degree angle).

Why is the Pythagorean theorem important?

The theorem provides a fundamental relationship in Euclidean geometry and has countless applications in construction, engineering, physics, and everyday problem-solving.

How accurate is this calculator?

This calculator provides results accurate to several decimal places, which is sufficient for most practical applications. For extremely precise work, consider rounding as appropriate for your specific needs.

Can I use this for non-right triangles?

No, the Pythagorean theorem only applies to right triangles. For non-right triangles, you would need to use other formulas such as the Law of Cosines.

Example Calculations

Example 1: Standard 3-4-5 Triangle

Given:

  • Base (a) = 3 feet
  • Height (b) = 4 feet

Solution:

c = √(a² + b²)

c = √(3² + 4²)

c = √(9 + 16)

c = √25

c = 5 feet

Example 2: Roof Pitch Calculation

Given:

  • Half the span (a) = 12 feet
  • Rise (b) = 8 feet

Solution:

Rafter length (c) = √(a² + b²)

c = √(12² + 8²)

c = √(144 + 64)

c = √208

c ≈ 14.42 feet

Related Geometry & Trigonometry Calculators

Diagonal Length Calculator

Calculate the diagonal length of a rectangle using its width and height measurements in feet.

Rectangular dimensions Calculate

Right Triangle Hypotenuse

Find the hypotenuse of a right triangle using the Pythagorean theorem with sides measured in feet.

Pythagorean theorem Calculate

Arc Length Calculator

Calculate the length of an arc based on radius and angle measurements in feet.

Circular segment Calculate

Chord Length Calculator

Determine the length of a chord in a circle based on radius and angle in feet.

Circle geometry Calculate

Sector Area Calculator

Calculate the area of a sector of a circle in square feet based on radius and angle.

Circular section Calculate

Polygon Perimeter Calculator

Find the perimeter of regular and irregular polygons with sides measured in feet.

Multi-sided figures Calculate

Circle Circumference

Calculate the circumference of a circle in feet using radius or diameter measurements.

Circle measurement Calculate

Cone Surface Area

Calculate the total surface area of a cone in square feet using radius and height.

3D geometry Calculate

Pyramid Surface Area

Find the total surface area of a pyramid in square feet based on base dimensions and height.

3D shapes Calculate

Slope Length Calculator

Calculate the length of a slope in feet using horizontal distance and height difference.

Incline measurement Calculate