1.The points A(x1,y1),B(x2,y2) and C(x3,y3) are the vertices of triangle ABC.
(1)The median from A meets BC at D.What are thEcoordinates of the point D?
(2)Find the coordinates of the point P on AD such that AP : PD = 2:1
(3)Find the coordinates of points Q and R on medians BE and CFrespectivelysuch that BQ : QE = 2:1 Aand CR : RF = 2 :1.
(4)What are the coordinates of the centroid of the triangle ABC?
SOLUTION : What are the coordinates of the centroid of the triangle ABC?
Given: The points A(x1,y1),B(x2,y2) and C(x3,y3) are the vertices of triangle ABC.
As we know that the centroid of a triangle is the point of concurrency of the medians.
The centroid G of the triangle ABC, divides the median AD, in the ratio of 2 : 1.
AG/AD = 2/1
Since,
D is the midpoint of BC
∴Coordinates of D are (x2+x3/2, y2+y3/2)
Using the section formula,
The coordinates of G are
⇒(2(x2+x3/2)+1.x1/2+1, 2(y2+y3/2)+1.y1/2+1)
⇒ Coordinates of G are [(x1+x2+x3)/3, (y1+y2+y3)/3].