Adjacent angles are created. An adjacent angles are two angles that share a common side and vertex (next to each other). A vertical angle is two angles directly across from each other (same degrees). Two angles with an added sum of 90 degrees is called a complementary angle. A supplementary angle is two angles that equal 180 degrees. Corresponding angles are in the same place but on a different angles (same degrees). Same side angles are in the same area on a line. Alternate interior angles are on opposite sides of the inner part of an angle (same degrees). Alternate exterior angles are on opposite sides on the outside of the parallel lines (same degrees).
Similar triangles are proportional triangles with the same degrees per corner. You can find the missing angle of a triangle by adding up the two angles and subtracting it from 180.