Question

The coordinates of the centroid I of triangle PQR are (2, 5). If Q = (-6, 5) and R = (7, 8). Calculate the coordinates of vertex P. 

Answer 1

Let G be the centroid of Δ PQR whose coordinates are (2 , 5) and let (x , y) be the coordinates of vertex P.

Coordinates of G are ,

G (2 , 5) = G ${\displaystyle (\frac{\text{x}-6+7}{3},\frac{\text{y}+5+8}{3})}$

${\displaystyle 2=\frac{\text{x}+1}{3},5=\frac{\text{y}+13}{3}}$

6 = x + 1  , 15 = y + 13

x = 5  , y =2

coordinates of vertex P are (5 , 2)