Right Triangle Calculator Mathematics

Right triangle

Instant calculation of sides, area and perimeter

a b c
Fill in any 2 sides
for the calculator to find the third
Side sought:
? ≈ 0
Catet (a) -
Catet (b) -
Hypotenuse (c) -
Area (S) -
Perimeter (P) -

Right Triangle Calculator

📐 Pythagorean Theorem in action

This calculator solves the main problem of geometry and construction: finding the unknown side of a right triangle if the other two are known.

💡 The formula is simple: c² = a² + b².
Where a and b are the legs (the sides at the right angle), and c is the hypotenuse (the longest inclined side).

Where is this used in practice?

We use this calculation more often than it seems, especially in construction and renovation:

Больше по теме: Area of ​​figures
Square📏 Calculation of room area (m²) online A simple tool for calculating the square footage of walls, floors or ceilings. Helps to know exactly the scope of work before renovating or purchasing real estate.
Figures📏 Instant calculation of the volume of geometric shapes Our tool helps calculate volume (capacity) for a wide variety of objects - from simple boxes to complex tanks.
Figures📐 Online calculation of perimeter (P) for any shapes The perimeter is the total length of the shape's border. Our calculator allows you to instantly calculate this value for 15+ geometric shapes: from a simple square to complex polygons.
  • Roof construction: Calculation of the length of the rafters if the height of the ridge and the width of the house are known.
  • Design of stairs: To find out the length of the stringer (base of the stairs), you need to know the height of the floor and the length of the opening. For a more detailed calculation of steps, we recommend our specialized stairs calculator.
  • Marking the foundation: Checking right angles using the “Egyptian triangle” method (aspect ratio 3:4:5).
  • Earth work: Calculation of the length of the path along the diagonal of the site.

📌 Useful tips

To ensure accurate results:

  1. Keep track of units of measurement. You cannot add meters and centimeters. If the data is in different quantities, use length converter before calculating.
  2. Remember that the hypotenuse is always longer than any of the legs. If it turns out differently for you, check the entered data.

Frequently asked questions (FAQ)

🔹 How to find the area of a triangle, knowing the sides?

This calculator only finds the length of the sides. But if you have already learned both sides (a and b), the area of ​​a right triangle is: (a × b) / 2. For complex shapes, use figure area calculator.

🔹 What are leg and hypotenuse in simple words?

Imagine a slide. The ground and the vertical ladder are legings (they form an angle of 90 degrees). And the slope itself along which you slide is the hypotenuse.

🔹 Why can’t you enter two hypotenuses?

By definition, a right triangle can have only one hypotenuse - it lies opposite the only right angle.

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