Mid-point of the line-segment joining the points A(3, 4) and C(9, 4) is:
Midpoint of the line segment joining (x1,y1) and (x2,y2) is given by (x1+x22,y1+y22)
∴ Mid-point of the line-segment joining the points (3, 4) and (9, 4) = (3+92,4+42) = (6,4)