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Area of a Right Triangle Calculator

How to find the area of a right triangle? What's the area of a right triangle formula? Check it out with this area of a right triangle calculator.

Clear
Area6the two legs are perpendicular, so they are base and height
Hypotenuse5
Perimeter12
Height on the hypotenuse2.4
Angles36.8699°, 53.1301°, 90°

The formula

A = ½ × leg × leg

What always holds

  • The three angles add to 180°, without exception.
  • Any two sides must add to more than the third — the triangle inequality. Sides of 4, 5 and 12 cannot close.
  • The longest side always faces the largest angle.
  • Area = ½ × base × height for any triangle, with the height measured perpendicular to that base.

Which formula to reach for

With three sides, use Heron’s formula. With a base and its height, use ½bh. With two sides and the angle between them, use ½ab·sin C. With a right angle, the two legs are already base and height, so the area is just half their product.