Question

Find the third vertex of a $△ABC$ if two of its vertices are B(-3, 1) and C(0, -2), and its centroid is at the origin.

Answer 1

Centroid $(X,Y)=\frac{x_1+x_2+x_3}{3},\frac{y_1+y_2+y_3}{3}$

$\Rightarrow (0,0)=\frac{-3+0+x_3}{3},\frac{1-2+y_3}{3}$

Solving, we get $x_3=3$ and $y_3=1$