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Right Triangle Calculator

Calculate the hypotenuse, area, and the angle opposite one leg of a right triangle.

 

 

Hypotenuse
Area
Angle opposite a (°)

About this calculator

Use this calculator to complete a right triangle from the two legs that meet at the 90° corner. The longest side, the hypotenuse, lies opposite the right angle. A 3-4-5 triangle is the classic integer example: legs 3 and 4 give hypotenuse 5 and area 6.

The formulas are: hypotenuse c = √(a² + b²) (Pythagoras), area = a b / 2, and the angle opposite leg a is arctan(a / b), reported in degrees. The other acute angle is 90° minus that result.

Use the same length unit for both legs. The hypotenuse stays in that unit; area is in that unit squared; the angle is in degrees.

Leg a: One side of the right angle.

Leg b: The other side of the right angle.

Hypotenuse: Side opposite the right angle, √(a² + b²).

Area: Interior of the triangle, a b / 2.

Angle opposite a (°): Acute angle opposite leg a, in degrees.