Let's put more details in the given figure.
From the figure shown, it appears that Arc KM, Arc KL and Arc LN covers half of the circle.
Thus, the total sum of the three mentioned arcs is 180°.
For us to find the measure of ∠LJN, let's first determine the measure of Arc KM.
We get,
Therefore, the measure of Arc KM is 10°.
Let's now determine the measure of ∠LJN.
For this, the following equation will be applied.
In this problem, the formula will be:
Therefore, the measure of ∠LJN is 23°