Vertically Opposite Angles (Jaclyn Schramm Part 3)
This picture proof shows how vertically opposite angles of two intersecting lines are congruent. This picture proof helps show that even when the lines are moved within the distance between the two points on each line, the vertically opposite angles will always be equal. The two lines that are intersecting each other are not perpendicular to one another, they just cross each other at a point. The intersection point must stay within the points on the line that are created because if the intersection point goes outside of the points, they will not be equal anymore (because the angles were measured with these points).