you first find the square of each side, the side facing angle B is b, the side facing angle A is a, and the side facing angle C is c
use the formula for distance between two points:
a²=BC²=36+64=100
b²=AC²=272
c²=AB²=164
the median from angle B is: m(b)=√[(2a²+2c²-b²)/4]
plug in all the numbers, I get the answer m(b)=√64=8