In a particular region there is a u

In a particular region there is a uniform current density of
15 A/m2 in the positive z direction. What is the value of
when that line integral is calculated along the three straight-line
segments from (x, y, z) coordinates (4d, 0,
0) to (4d, 3d, 0) to (0, 0, 0) to (4d, 0, 0),
where d  20 cm?