Question

which angles are vertical to ∠9? select all that apply.

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are opposite each other and have equal measures.

Step2: Identify intersecting lines

In the given diagram, we look at the intersection points. The angles at the intersection where ∠9 is located are considered.

Step3: Determine vertical angles

∠9 and ∠11 are vertical angles as they are opposite each other at the intersection. Also, by considering the transversals and parallel - line relationships (if applicable, though not necessary for vertical - angle identification here), we can see that ∠2 and ∠9 are vertical angles (formed by the intersection of the relevant lines), ∠8 and ∠9 are vertical angles, and ∠3 and ∠9 are vertical angles.

Answer:

∠2, ∠8, ∠11, ∠3