Jan 062012
Understanding the basic properties of angles is a critical skill that will likely be tested in multiple questions on the SAT exam.
•The vertex of an angle is the point at which two sides of an angle intersect.
•Angles may fall into any one of the following categories:
–An acute angle is an angle that measures less than 90°.
–An obtuse angle is an angle that measures more than 90°.
–An right angle is an angle that measures exactly 90°.
–An straight angle is an angle that measures exactly 180°.
•Two angles whose sum is 90° are said to be complementary.
•Two angles whose sum is 180° are said to be supplementary.