ClipArt ETC
Angles 1 and 2 are adjacent angles. Two angles with a common vertex and a common side between them are adjacent angles.

Adjacent Angles

Angles 1 and 2 are adjacent angles. Two angles with a common vertex and a common side between them are…

Illustration showing a triangle with an exterior segment drawn to show and exterior angle. This can be shown to show adjacent angles ACB and ACD as well.

Triangle With Segment Extended for Exterior Angle

Illustration showing a triangle with an exterior segment drawn to show and exterior angle. This can…