How are vertical and other angles related?

Vertical angles are formed when two lines intersect, creating two pairs of opposite angles that are equal in measure. For example, when two lines cross, the angles opposite each other at the intersection are vertical angles and are always congruent. Other angles formed at the intersection, such as adjacent angles, are supplementary, meaning they add up to 180 degrees. Thus, while vertical angles are equal, adjacent angles are closely related through their sum.