Problems in varying levels of mathematics require that the area of a triangle be known, or found.  We  know that there are two formulae for determining the area of a triangle, based upon information that is either given or can be easily determined:
 

 

There is an additional formula, called Heron's formula, that will let you determine the area of a triangle given the lengths of the three sides.  (This formula is often called "Hero's Formula".)

There is also another trigonometric formula.  If two angles and a side are known, the area can be found by using the formula stated below.  The third missing angle is calculated before the formula is used.