Plane Geometry Review : Triangle Area calculation

Area Formulas

1.  Given base and altitude

Triangle: Given base and height

Area = 1/2 (b)(h)

2. Given two sides and an Angle

 Triangle:  Given 2 sides and angle

Area = 1/2 (a) (b)sin θ

3. Given 3 sides

Triangle Given 3 sides a,b,c

Area = sqrt (s(s-a)(s-b)(s-c))----->  Heron's Formula  

where s= (a+b+c)/2

4. Triangle inscribed in a circle

r= radius of the circle 

Area = (a b c)/ 4r

5. Given a circle inscribed in a Triangle

r = radius of the circle

Area  =  rs 

s = ( a+b+c/) 2

6. Circle escribed by the triangle

where a is the side tangent to the circle

Area =  r (s-a)

s = ( a+b+c/) 2