1) If a triangle ABC with two vertices A(5,4,6) and B(1,-1,3) has its centroid at (103,2,113) then the third vertex C is A) (4,2,3) B) (-4,-3,2) C) (4,3,2) D) (2,4,3) Answer: Option CExplanation: We have △ ABC A=(5,4,6). B=(1,-1,3), C=(x,y,z) Centroid of △ ABC is (103,2,113) ∴ 103=5+1+x3⇒x=4 2=4−1+y3⇒y=3 113=6+3+z3⇒z=2 ∴ Vertices C= (4,3,2)