1. Segment Addition Postulate
DO NOW 9/15:
In the problem below, AB = 9 and AC = 14. Describe and correct the error made.
Segment Addition Postulate
Agenda
HW Review (10 min)
Segment Addition Jigsaw (25 min)
Congruent Segments/Midpoint (10 min)
Debrief (10 min)

2. HW Review

3. Segment Addition Jigsaw
Each person starts with a sheet with segment addition problems on it. There will be a timer for each round.
Round 1: Draw a diagram for each problem (2 min)
Round 2: Write an equation for each problem (8 min)
Round 3: Subtitute numbers into equation for each problem (5 min)
Round 3: Solve each problem (and CHECK YOUR ANSWER!!) (10 min)
**Between each round, make sure the person before you was correct!**

4. Congruent Segments and Midpoints
**MUST BE IN NOTES!**
Congruent – two figures that are the same size and shape
Midpoint – the point that divides the segment into two congruent segments.
Shown on diagrams as“tic marks”

5. Midpoint of a Segment: Practice

6. Debrief How are congruent segments related to midpoints?
Why is it important to follow each step (diagram, equation, substitution, solution) when using segment addition?

7. Naming Angles / Angle Pairs
DO NOW 9/16:
If M is the midpoint of LN, then what is the length of LM?
x + 6 cm
5x – 2 cm L M N
Naming Angles / Angle Pairs
Agenda
Naming Angles (10 min)
Vertical Angles/Adjacent Angles (5 min)
Supplementary/Complementary Angles (5 min)
Angle Addition Postulate (15 min)
Debrief (10 min)

8. Pool/Snooker Angles What angles are involved in the game?
2014 World Champ Video - $1.9 million prize
What angles are involved in the game?

9. Naming Angles We name angles with three points (capital letters).
The middle letter is always the vertex.
Sometimes textbooks and tests will label an angle with a number on the interior of the angle.
If there is only one angle, we can name that angle using ONLY the vertex. However, if there are more than one angle, we need to use all 3 points.

10. Supplementary and Complementary Angles
Complementary Angles – two angles that add up to 90°
Supplementary Angles – two angles that add up to 180°

11. Other Angle Pairs
**MUST BE IN NOTES!**
Vertical Angles – any pair of angles that share a vertex but don’t share any sides
Adjacent Angles – any pair of angles that share a vertex and share one side
Linear Pair – a specfic type of adjacent angles that are supplementary

12. Angle Addition Postulate
**MUST BE IN NOTES!**
If Z is a point in the interior of ∠ABC, then m∠ABZ + m∠ZBC = m∠ABC.

13. Debrief (EXIT TICKET)
Can two obtuse angles be supplementary? Why or why not?
Exit Ticket: Angle Addition Worksheet

14. Segment and Angle Addition Postulate
DO NOW 9/17:
In the diagram below, name:
an acute angle
an obtuse angle
a vertical pair
a linear pair
a complementary pair
Segment and Angle Addition Postulate
Agenda
Angle Bisectors (10 min)
Angle Addition with Angle Bisectors (10 min)
Clock Angles (10 min)
Debrief (10 min)

15. HW Review

16. Angle Bisector
**MUST BE IN NOTES!**
Angle bisector – a ray that divides an angle into two congruent angles.
∠CAB ≅ ∠BAD

17. 4-Corner Drill
In teams, solve the problem on the board. When you have an answer, head to the corner with the correct answer choice.
1 point – First team at correct answer
1 point – Ending up at correct answer
1 point – Explaining answer correctly

18. Segment Addition

19. Segment Addition with Midpoint

20. Angle Addition

21. Angle Addition with Bisectors

22. Debrief
What helped speed things up in your group? What slowed things down? How can you utilize strategies from today to help you on your quiz tomorrow?

23. Angle and Segment Addition Quiz!
DO NOW 9/18
Angle and Segment Addition Quiz!
Angle Bisectors
Agenda
Angle and Segment Addition Quiz (20 min)
Clock Angle Bisectors (20 min)
Debrief (10 min)

24. Angles on Parallel Lines
DO NOW 9/19:
Find the value of x and the m∠DEC
Angles on Parallel Lines
Agenda
Note Check!
Clock Video (5 min)
Clock Angles Activity (20 min)
Formula Creation (10 min)
Debrief (10 min)

25. There’s No Time Like Math Time!
“How many times is the second hand exactly between the minute and hour hand?”
Watch this until you go crazy.
Then watch this.
Then use this.
Is this an angle bisector?

26. What information will we need to figure this out?

27. …Maybe this will help?
t = # of seconds (since 12:00:00 or zero degrees)
S = 6t
M = t/10
H = t/120
Measure between the two hands has to be equal, and add up to 360°
M – S = S – H + 360

28. Debrief
What previous math skills did you draw on to solve this problem?
Extension (Classwork Extra Credit):
How many times a day are all 3 hands aligned?
What are 3 times when the Hour hand is directly between the second and minute hand?

29. HW This Weekend
Come up with a statement that fits the following structure:
“ If _________________, then ___________________.”
...and DOESN’T seem logical!
Ex. “If there is a forest fire, then fish will die.”