SOLUTION: please help me solve this question The vertices of a triangle are (1,a)(2,b)(c square,-3):- (1) Prove that its centroid cannot lie on the Y - axis. (2) Find the condition that

Algebra ->  Statistics  -> Correlation -> SOLUTION: please help me solve this question The vertices of a triangle are (1,a)(2,b)(c square,-3):- (1) Prove that its centroid cannot lie on the Y - axis. (2) Find the condition that      Log On


   



Question 1011927: please help me solve this question
The vertices of a triangle are (1,a)(2,b)(c square,-3):-
(1) Prove that its centroid cannot lie on the Y - axis.
(2) Find the condition that the centroid may lie on the X - axis

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
(1) The centroid of a convex polygon is inside the polygon.
Since The x-coordinates of A, B, and C are all positive number,
so will be the x-coordinate of the centroid,
meaning that it will lie to the right of the y-axis.
Another way;
The x-coordinate of the centroid is the average of the x-coordinates of the vertices,
so it is %281%2B2%2Bc%5E2%29%2F3=%283%2Bc%5E2%29%2F3=1%2Bc%5E2%2F3%3E=1 ,
so the centroid lies on the line x=1 or to its right,
at a distance of at least 1 to the right of the y-axis.

(2) The y-coordinate of the centroid is the average of the y-coordinates of the vertices,
so it is %28a%2Bb-3%29%2F3 .
For the centroid to be on the x-axis, that y-coordinate must be zero:
%28a%2Bb-3%29%2F3=0<-->a%2Bb-3=0<-->highlight%28a%2Bb=3%29 .