Question

Two vertices of a triangle are(3, -5) and (-7, 4). If its centroid is (2, -1), find the third vertex

Answer 1

Let the coordinates of the third vertex be (x, y). Then,$\frac{x+3-7}{3}=2and\frac{y-5+4}{3}=-1$$\Rightarrow x-4=6andy-1=-3$

$\Rightarrow x=10andy=-2$

Thus,the coordinates of the third vertex are (10, -2).