The midpoint between two points can be found by averaging their coordinates. This is done below:
[tex]\begin{gathered} x_m\text{ = }\frac{x_1+x_2}{2} \\ y_m\text{ = }\frac{y_1+y_2}{2} \end{gathered}[/tex]Using the above expressions we can apply the coordinates of the points we want to find, A(2,13) and O(-4,3).
[tex]\begin{gathered} x_m\text{ = }\frac{2\text{ -4}}{2} \\ x_m\text{ = }\frac{-2}{2} \\ x_m\text{ = -1} \end{gathered}[/tex][tex]\begin{gathered} y_m\text{ = }\frac{3+13}{2} \\ y_m\text{ = }\frac{16}{2} \\ y_m\text{ = 8} \end{gathered}[/tex]The coordinates of the midpoint are (-1,8).
