Angle Addition Postulate part 2, adjacent angles, congruent angles bisector of an angle, diagrams

1. 
A
B
O C

2.  Definitions:
› Congruent angles (≅∠s): Angles that have equal
measures.
› Adjacent angles: two angles in a plane that have a
common vertex and a common side but no
common interior points.
1 2
1 2
3
4
4
3

3. › Bisector of an angle: the ray that divides the angle
into two congruent, adjacent angles.
 m∠MAH = m∠TAH
 ∠MAH ≅ ∠TAH
 AH bisects ∠MAT
40°
40°
M
A T
H

4.  The following are things that you can conclude from the
diagram shown:
› All points shown are coplanar.
› AB, BD, and BE intersect at B.
› A, B, and C are collinear.
› B is between A and C.
› ∠ABC is a straight angle.
› D is in the interior of ∠ABE.
› ∠ABD and ∠DBE are adjacent angles.
A
B
C
D
E