Answer:
Angle 5
Step-by-step explanation:
The orange arrows on lines r and c mean that these lines are parallel.
Alternate Interior Angles Theorem
If a line intersects a set of parallel lines in the same plane at two distinct points, the alternate interior angles that are formed are congruent.
In the given figure, the parallel lines r and c are intersected by 2 straight lines and the following pairs of alternate interior angles are formed:
∠3 and ∠5
∠2 and ∠4
Therefore, ∠3 and ∠5 and congruent, and ∠2 and ∠4 are congruent.
∠1 and ∠6 are vertically opposite angles. Vertically opposite angles are created when two straight lines intersect, and are congruent. Therefore, ∠1 and ∠6 are congruent.