How many ways can we find the area of a triangle? Topic Index | Algebra2/Trig Index | Regents Exam Prep Center

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:

 The basic formula: Given:  base and altitude to that base The trigonometry based formula:  Given:  two sides and the included angle

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".)

 Heron's formula: where Given:  the three sides (s is called the semiperimeter, or half the triangle's perimeter)

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.

 Given:  two angles and a side

 Topic Index | Algebra2/Trig Index | Regents Exam Prep Center Created by Donna Roberts