The vertices of a triangle are A(2,3), B(8,5) and C(4,9).
a. (a) Find the mid-point M of the side BC.
b. (b) Determine the coordinates of the centroid G of the triangle.
c. (c) Show that the points A, M and G are collinear.
d. (d) In what ratio does G divide the segment AM? Justify your answer.