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1.4 Notes
Geometry
Measuring & Classifying Angles
Angle: two rays with the same endpoint
Example 1: Name the three angles in this diagram.
Classifying Angles:
A
A
A
acute
A
right
obtuse
Angle Addition Postulate:
If D is in the interior of  ABC, then m  1 + m  2 = m  ABC
A
D
1
2
B
C
Example 2: Given m  1=43 o and m  2=70 o , find m  ABC.
C
1
B
2
A
D
straight
Example 3: Given m  GFJ = 155o, find m  GFH and m  HFJ. (*Hint: Find x first.)
Example 4: Given  VRS is a right angle, find m  VRT and m  TRS.
**Two angles are congruent if they have the same measure.
Example 5: Identify all pairs of congruent angles in the diagram. If m  P = 120o, find m  N.
Angle Bisector: a ray that divides an angle into two congruent angles
Example 6: WY bisects  XWZ and m  XWY= 29
Find m  XWZ.