Midpoint formula is used to determine the exact center of a line.
If these two lines are diagonals of the parallelogram then their centers must be same.
Let us apply it on AC line first. A = (3, 7) C = (10, 6)
[tex](x,\text{ y) = }\frac{(3+10)}{2},\text{ }\frac{7+6}{2})=(\frac{13}{2},\text{ }\frac{13}{2})\rightarrow\text{ Coordinates of the mid point on AC line}[/tex][tex](x,y)\text{ = (}\frac{9+4}{2},\frac{10+3}{2})=(\frac{13}{2},\frac{13}{2})\rightarrow\text{ BD line coordinates}[/tex]
