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,

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

$\Rightarrow x-4$ = 6 and y - 1 = -3

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

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