In geometry, adjacent angles are angles that have a common ray coming out of the vertex going between two other rays. In other words, they are angles that are side by side, or adjacent.
Complementary adjacent angles
A pair of angles are complementary if the sum of their measures is 90°.
A pair of angles are supplementary if the sum of their measures is 180°.
If the two complementary 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 right angle.
In Euclidean geometry, the two acute angles in a right triangle are complementary, because there are 180° in a triangle and 90° have been accounted for by the right angle.
Adjacent angles are angles that will never meet and are marked with two lines on the line.
Supplementary angles are angles in which both have the sum of 180°.
An angle with a ray connected to a common point down the center. In Geometry, two angles are adjacent angles if they share a common vertex and side, but have no common interior points.
External links
- Complementary Angles animated demonstration. With interactive applet
- Supplementary Angles animated demonstration. With interactive applet
- Angle definition pages with interactive applets that are also useful in a classroom setting. Math Open Reference
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