Median Length in Triangle ABC

In a coordinate plane, consider triangle ABC with vertices A(1, 2), B(5, 6), and C(4, -2). Find the length of the median from vertex A to side BC.

Recall that the length of the median from a vertex to the opposite side can be calculated using the formula:

$M = \sqrt{\frac{2AB^2 + 2AC^2 - BC^2}{4}}$

where $M$ is the length of the median, and $A$, $B$, and $C$ are the lengths of the triangle's sides.