In the given configuration of intersecting lines, angles 1 and 4, as well as angles 2 and 3, are vertical angles because they are opposite each other and share a common vertex at the point of intersection.
Vertical angles are pairs of angles formed by intersecting lines where the angles are opposite each other. In the given scenario with a horizontal line bisected by a transversal, you have angles 1, 2, 3, and 4. Vertical angles are always opposite to each other, and in this case, angles 1 and 4 are vertical angles, and angles 2 and 3 are also vertical angles.
Angle 1 and angle 4 share the same vertex, which is the point of intersection of the bisecting transversal and the horizontal line. They are on opposite sides of the intersection point and are equal in measure. Similarly, angle 2 and angle 3 are vertical angles because they are opposite to each other, formed by the intersection of the transversal and the horizontal line.