Area Of A Triangle

The area of a ΔABC with vertices is given by area

Proof: Let be the vertices of the given ΔABC.

Draw AP, BM and CN perpendiculars to the x-axis.

∴ Area of ΔABC

= ar (trap. BMPA) + ar (trap.. APNC) − ar (trap. BMNC)

CONDITION FOR COLLINEARITY OF THREE POINTS

Let the given points be .

Then A, B and C are collinear

⇒ area of ΔABC = 0