1. 1.3: Angles -angle pairs GSE
M(G&M)–10–2 Makes and defends conjectures, constructs geometric arguments, uses geometric properties, or uses theorems to solve problems involving angles, lines

2. Activity (handout):
– Exploring Angle Relationships
Questions 1 - 7

3. Types of Angle Relationships
Adjacent Angles
Vertical Angles
Linear Pairs
Supplementary Angles
Complementary Angles

4. 1) Adjacent Angles
Adjacent Angles - Angles sharing one side that do not overlap

5. 2)Vertical Angles
Vertical Angles - 2 non-adjacent angles formed by 2 intersecting lines (across from each other). They are CONGRUENT !! 1

6. 3) Linear Pair
Linear Pairs – adjacent angles that form a straight line. Create a 180o angle/straight angle.

7. 4) Supplementary Angles
Supplementary Angles – two angles that add up to 180o (the sum of the 2 angles is 180)
How are they different from linear pairs?

8. 5) Complementary Angles
Complementary Angles – the sum of the 2 angles is 90o
= 180

9. Find the unknown angle measures

10. Handout – Part II

14. In class practice
Complementary & supplementary angles
Page 70: 1-10, 15-28
Vertical angles
Page 78: 1-33, 51-53

15. Angle Bisector
A ray that divides an angle into 2 congruent adjacent angles.
BD is an angle bisector of <ABC. A D B C

16. Angle Bisector
A ray that divides an angle into 2 congruent adjacent angles. A
Angle ABD is CONGRUENT to angle DBC D B C

17. Ex: If FH bisects <EFG & m<EFG=120o, what is m<EFH?

18. Last example: Solve for x.
BD bisects ABC A D
x+40o
x+40=3x-20
40=2x-20
60=2x
30=x
3x-20o C B
Why wouldn’t the Angle Addition Postulate help us solve this initially?

19. In class practice
Angle bisectors
Page 64: 1-22, 28-30
Homework: Worksheets 2.2A, 2.3A, 2.4A