Right triangle

A right-angled triangle is a triangle that has one right angle (equal to 90 degrees), or a rectangle with a diagonal drawn, which will divide it into two rectangular triangles. The side opposite the right angle is called the hypotenuse (side c in the figure). The sides adjacent to the right angle are called legs (or catheti, singular: cathetus). From this follows that the area of a right-angled triangle can be found by dividing the area of the rectangle in half as mentioned in the formula. The sides of the rectangle, in this case, will be simultaneously the legs of the resulting triangle, therefore its area is equal to the product of the legs, divided by two.