Question

When two lines intersect, they form four angles. You can label them 1, 2, 3, and 4. The two angles across from each other are called vertical angles. Vertical angles are always congruent, or have the same measurement. Congruent angles are marked with matching sets of angle arcs. In the figure below, angle 2 and angle ________ are congruent.

Answer 1

Angle 4

Explanation:

The explanation in the question is pretty complete. The only thing that could better is if the diagram showed slightly different markings to show that Angle 2 and Angle 4 are vertical angles that have the same measure. AND Angle 3 and Angle 1 are another pair of vertical angles that have the same measure. I always think of a pair of scissors when I think of vertical angles.