| A | B |
|---|
| Acute angle | An angle with a measure less than 90 degrees. |
| Adjacent angles | Angles in the same plane that have a commom vertex, and a common side, but no interior points in common. |
| Amount of turn | A unit of angle measure used when an angle is viewed as the figure formed by turning a ray about its endpoint. |
| Bisector of an angle | Given an angle, this is the ray that has the same endpoint as the sides of the angle, that passes through the interior of the angle, so that the two angles formed are congruent. |
| Center of a circle | The point in the interior of a circle that all the points of the circle are the same distance from. A circle is named by this point. |
| Chord | Any line segment whose endpoints are on the circle. |
| Circle | All points in the same plane that are the same distance from a point. |
| Complement of an angle | An angle that has a measure equal to 90 degrees - the measure of the given angle. |
| Complementary angles | Two angles whose measures add up to 90 degrees. |
| Congruent Angles | Two or more angles that have the same measure. |
| Degree | A unit of angle measure equal to 1/360 turn. |
| Diameter of a Circle | A segment the contains the center of a circle and has its endpoints on the circle. |
| Equidistant | The same distance |
| Measure of an Angle | A number in degrees or amount of turn associated with an angle. It is denoted, m/ |
| Obtuse Angle | An angle with a measure more than 90 degrees. |
| Protractor | An instrument used to measure angles. |
| Radius of a Circle | A segment joining the center of a circle to any point on the circle. |
| Right Angle | An angle with a measure of 90 degrees. |
| Straight Angle | An angle with a measure of 180 degrees. |
| Supplement of an Angle | An angle that has a measure equal to 180 degrees - the measure of the given angle. |
| Suppplementary Angles | Two angles whose measures add up to 180 degrees. |
| Vertical Angles | Two angles whose sides form two pair of opposite rays. |
