A right-angled triangle is a triangle in which one angle is a right angle (that is, a 90-degree angle). The relation between the sides and angles of a right triangle is the basis for Trigonometry.
The side opposite the right angle is called the hypotenuse. The sides adjacent to the right angle are called legs ..
If the lengths of all three sides of a right triangle are integers, the triangle is said to be a Pythagorean triangle and its side lengths are collectively known as a Pythagorean Triple.
In a right triangle, if one leg is taken as the base then the other is height, so the area of a right triangle is one half the product of the two legs.

Find the area of a triangle with base 18 cm and height 7 cm.