Answer:
100 degrees
Explanation:
From the given figure, we can see that the sum of <5 and 80 degrees will be 180 degrees;
[tex]\begin{gathered} \angle5+80=180\text{ (sum of angles on a straight line)} \\ \angle5=180-80 \\ \therefore\angle5=100^{\circ} \end{gathered}[/tex]We know that alternate interior angles are always equal and we can see from the figure that <5 and <4 are alternate interior angles, so we have that;
[tex]\angle5=\angle4=100^{\circ}[/tex]