Question

Question 1 (ii)
Find the area of the triangle whose vertices are:
(ii) (-5, -1), (3, -5), (5, 2)

Answer 1

Let $(x_1,y_1)=(-5,-1)$, $(x_2,y_2)=(3,-5)$ and $(x_3,y_3)=(5,2)$,
Area of a triangle
$=\frac{1}{2}\left\{x_1\right(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2\left)\right\}$
=$\frac{1}{2}[-5\left\{\right(-5)-(2\left)\right\}+3(2-(-1))+5\{-1-(-5\left)\right\}]$
= $\frac{1}{2}\{35+9+20\}$
= 32 square units