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Right Triangle Calculator

Use our free right triangle calculator to compute the hypotenuse, area, and perimeter of a right triangle. Enter the lengths of the two legs and get instant results.

Math

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Side A (leg)

Side B (leg)

Formula

A right triangle is a triangle with one 90° angle. The two shorter sides are called legs (a and b), and the longest side opposite the right angle is the hypotenuse (c).

c = √(a² + b²), A = ½ × a × b

Percentage: The percentage value you want to apply

Number: The original number or value

Result: The calculated result

How It Works

1Enter the length of side A (one leg).
2Enter the length of side B (the other leg).
3Click Calculate to find the hypotenuse and area.
4The hypotenuse is computed using the Pythagorean theorem: c = √(a² + b²).
5The area is computed as A = ½ × a × b.

Examples

Right triangle with legs 3 and 4

1.Enter sideA = 3, sideB = 4.
2.Hypotenuse = √(3² + 4²) = √25 = 5.
3.Area = ½ × 3 × 4 = 6 units².

Result: Hypotenuse: 5.0000, Area: 6.0000

Right triangle with legs 5 and 12

1.Enter sideA = 5, sideB = 12.
2.Hypotenuse = √(5² + 12²) = √169 = 13.
3.Area = ½ × 5 × 12 = 30 units².

Result: Hypotenuse: 13.0000, Area: 30.0000

Frequently Asked Questions

A right triangle is a triangle with one angle equal to 90 degrees. The side opposite the right angle is called the hypotenuse.

Use the Pythagorean theorem: c = √(a² + b²), where a and b are the lengths of the two legs.

The area is half the product of the two legs: A = ½ × a × b. This works because the legs are perpendicular to each other.

Yes. The perimeter is P = a + b + c. Once you have the hypotenuse, simply add all three sides.

You can find the missing leg using: a = √(c² - b²) or b = √(c² - a²). Use our Pythagorean Theorem calculator.

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CalculateMe Team

Last updated: 2026-07-13

Right Triangle Calculator - Hypotenuse and Area | CalculateMe | CalculateMe