MathGloss/A/Area of triangle

Defintion
The area of a triangle can be found by multiplying the base times the one-half the height.The area of a triangle can be calculated in three ways. The most common expression for the area of a triangle is one-half the product of the base and the height (1/2AH). The height is formally called the altitude, and is equal to the length of the line segment with one endpoint at a vertex and the other endpoint on the line that contains the side opposite the vertex. Like all altitudes, this segment must be perpendicular to the line containing the side.

Examples
The area of triangle that its bas 10 cm and hight 4cm is $$1/2AH = 1/2 *10*4 =20 $$ cm 2