| A | B |
|---|
| An angle is formed by | two rays with a common endpoint |
| The common endpoint of the two rays that form an angle | vertex |
| You can name an angle by naming in the following order | ยท a point on one ray, the vertex and a point on the other ray |
| When using three points to name the angle, the vertex is | always named in the middle. |
| Identical curved mark inside different angles show that the angles are | congruent. |
| The measure of the angle DEC is written | m /_ DEC |
| protractor | used to measure an angle in degrees |
| When naming an angle by its vertex make sure | there is only one angle at the vertex |
| If D is in the interior of /_ ABC, then | m /_ ABD + m /_ DBC = m /_ ABC |
