The coordinates of the points are:
H (5, 3)
I (5, 8)
J (9, 8)
Given that H and I have the same x-coordinate, then the side length of side HI is obtained, subtracting the y-coordinates, as follows:

Given that I and J have the same y-coordinate, then the side length of side IJ is obtained, subtracting the x-coordinates, as follows:

The side length between H and I is 5 units
The side length between I and J is 4 units