A pair of angles is supplementary if their measurements add up to 180 degrees. If the two supplementary angles are adjacent (i.e. have a common vertex and share a side, but do not have any interior points in common) their non-shared sides form a straight line.
See also
External links
- Animated demonstration - Interactive applet and explanation of the characteristics of supplementary angles.
- Angle definition pages with interactive applets that are also useful in a classroom setting. Math Open Reference
