​ Can someone help me soon

First find  SN length     pythag theorem    4^4  + SN^2 = 22^2      SN = 21.6333   or 2 sqrt117

UM goes up  sqrt117  units  (Pythag theorem again with a line dropped from M)    for a horizontal distance of 6 units

sqrt117/6 = NX/4       yields NX = 2/3 sqrt 117         sooooo   SX =  2 sqrt 117  -  2/3 sqrt 117 =  4/3 sqrt(117)  units    (I think ! )

Not positive about this answer !

Important: The Median Theorem states that the medians of a triangle intersect at a point called the centroid that is two-thirds of the distance from the vertices to the midpoint of the opposite sides.

ST² - TN² = SN²                

SX / NX = 2 / 1

SX = 2/3 * SN