Right Triangle
A right triangle has a right angle (90º) and two acute angles.
Legs or Catheti
The catheti (singular: cathetus) are the sides opposite the acute angles and are the shorter sides of the right triangle.
Hypotenuse
The hypotenuse is the side opposite the right angle, and is the largest side of the right triangle.
Area of a Right Triangle
The area of a right triangle is equivalent to half the product of its legs.
Theorems
1 Pythagorean theorem
2
In all right triangles, the length one of the legs is a mean proportional between the hypotenuse and the projection on it.
3
In all right triangles, the height of the hypotenuse is a mean proportional between the two segments that it divides.
Examples
The hypotenuse of a right triangle measures 30 cm and the projection of a leg is 10.8 cm on the hypotenuse. Find the length of the other leg.
In a right triangle, the projections of the legs on the hypotenuse are 4 and 9 cm in length. Calculate the height of the triangle.
