Right Triangle Calculator

Your details

Load a well-known right triangle. You can then scale it by changing leg a.
A leg meeting the right angle. Leave blank if unknown.
units
The other leg meeting the right angle. Leave blank if unknown.
units
The longest side, opposite the right angle. Leave blank if unknown.
units
Acute angle facing leg a. Leave blank if unknown.
Acute angle facing leg b. Leave blank if unknown.
Supply the area with one side instead of a second side or angle.
units squared
StatusScalene right triangle
Solved
Leg a3units
Leg b4units
Hypotenuse c5units
Angle A (opposite a)36.8699deg
Angle B (opposite b)53.1301deg
Area6units squared
Perimeter12units
Semiperimeter (s)6units
Altitude to hypotenuse (h_c)2.4units
Altitude to leg a (h_a)4units
Altitude to leg b (h_b)3units
Inradius (r)1units
Circumradius (R)2.5units

Hypotenuse 5 units, area 6 sq units, inradius 1 units.

  • The two acute angles are 36.87 deg and 53.13 deg, which always sum to 90 deg in any right triangle.
  • The circumscribed circle has radius R = c/2 = 2.5 units because the hypotenuse is always the diameter of that circle (Thales theorem).
  • The inscribed circle has radius r = (a + b - c) / 2 = 1 units, where a and b are the legs and c is the hypotenuse.
  • You can solve the same triangle from a single leg plus one acute angle using SOHCAHTOA - no second measurement needed.

Next stepTry a preset (45-45-90 or 30-60-90) to explore special right triangles, or enter an area plus one side.

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