Question

If the centroid of the triangle ABC is (1, 1, 1 ) . If the coordinates A and B are (3, -5, 7) and (-1, 7, -6) respectively, then the coordinates C is

• A. (2, 1, 1)
• B. (1,2,1)
• C. (1, 1 ,2)
• D. (-1, 1 ,2)

Answer 1

The correct option is C

(1, 1 ,2)

$(\frac{3-1+x}{3},\frac{-5+7+y}{3},\frac{7-6+z}{3})=(1,1,1)\Rightarrow (\frac{2+x}{3},\frac{2+y}{3},\frac{1+y}{3})=(1,1,1)\Rightarrow (x,y,z)=(1,1,2)$