[tex]\large{\green{\underline{\underline{\bf{\orange{ANSWER:-}}}}}}[/tex]
The question and data provided in the information is that (<J ≈ <K) are congruent to each other. Then (<J + <L = 180°) here supplementary means that there sum tends to 180°. And we have also provided the value of <K = 71°.
Now as per question we can write that,
[tex]\longrightarrow\bf{ \angle j + \angle l = 180}[/tex]
[tex]\longrightarrow\bf{ \angle k + \angle l = 180 \: .... \: ( \angle j = \angle k)}[/tex]
Now substituting values,
[tex]\longrightarrow\bf{71 + \angle l = 180}[/tex]
[tex]\longrightarrow\bf{ \angle l = 180 - 71}[/tex]
[tex]\longrightarrow\bf{ \angle l = 109}[/tex]
