KJL and LJN are adjacent supplementary angles.
Adjacent angles share a side, and supplementary angles are 2 angles with a sum of 180°.
In the diagram, KJL is a right angle (90°).
You can look at LJN as an angle composed of two acute angles, LJM and MJN.
LJM = 56° and MJN = 34°.
56 + 34 = 90°.
So, we know angle LJN measures 90°.
Since KJL is 90° and LJN is 90°, they have a sum of 180°, making them supplementary angles. They share a side (JL) so they are adjacent as well.