1. Angles Acute angle (def)- angle measure less than 90° Right angle (def)- angle measure= 90° Obtuse angle (def)- angle measure greater than 90° Straight angle (def)- angle = 180° Interior of angle Exterior of angle

2. To Name an Angle- A. Use 3 letters (vertex in the middle) B. Number it. C. IF there is ONLY ONE angle with that vertex, you may use a single letter (the vertex). A D is NOT appropriate for this sketch b/c vertex 1 there are 3 angles with the vertex B. 2 C Congruent angles- angles that have = measures. - measure of an angle

3. Adjacent Angles (def)-2 coplanar angles that share a common ray. They must have a common vertex.

4. Complementary <‘s are 2 angles whose measures have a sum of 90. m<1 + m<2 = 90 Supplementary <‘s are 2 angles whose measures have a sum of 180. m<1 + m<2 = 180

5. ° or 50° 40°

6. or 145° 35°

7. Linear Pair (def)-adjacent angles whose non-common sides form a line. (describes) Linear Pairs are Supplementary. If <1 and <2 form a linear pair, then they are supplementary. m<1 + m<2 = 180

8. Angle Bisector(def)- is a ray that divides the angle into 2 congruent angles. A D B C

9. Angle Addition Postulate- sum of the parts = whole The angles must be adjacent. A D B C

10. Vertical Angles(def)- 2 nonadjacent angles formed by intersecting lines (describes) 1 4 2 3 If 2 angles are vertical, then they are congruent. (value)