In the figure below, lines AB and CD intersect each other at point O. The angle pairs (∠AOD, ∠COB) and (∠AOC, ∠BOD) are called ___.
In the figure below, lines AB and CD intersect each other at point O. Angles (∠ AOD, ∠ COB) and (∠ AOC, ∠ BOD) are called ___.