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 third vertex be (x,y). Then,

$\frac{x+3-7}{3}=2$ and $\frac{y-5+4}{3}=-1$

$x=10$ and $y=-2$

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