1. Bell Ringer Quiz
Choose the plane parallel to plane MNR
Classify the relationship between the angles
Angle 1 and Angle 5
Angle 8 and Angle 3
Angle 6 and Angle 4
3) The measures of two complementary angles are x + 54 and 2x. What is the measure of the each angle?

2. Groupwork: P176 #14-36 even
Turn in on one sheet with all group members names. Once you are done you will receive the homework.

3. Bellringer P178 #55 Show Work
Copy the postulates from 3-2 on your postulate sheet or into your notebook

4. Concept

5. 15  11 Corresponding Angles Postulate
Use Corresponding Angles Postulate
A. In the figure, m11 = 51. Find m15. Tell which postulates (or theorems) you used.
15  11 Corresponding Angles Postulate
m15 = m11 Definition of congruent angles
m15 = 51 Substitution
Answer: m15 = 51
Example 1

6. 16  15 Vertical Angles Theorem
Use Corresponding Angles Postulate
B. In the figure, m11 = 51. Find m16. Tell which postulates (or theorems) you used.
16  15 Vertical Angles Theorem
15  11 Corresponding Angles Postulate
16  11 Transitive Property ()
m16 = m11 Definition of congruent angles
m16 = 51 Substitution
Answer: m16 = 51
Example 1

7. A. In the figure, a || b and m18 = 42. Find m22.
C. 48
D. 138
Example 1a

8. B. In the figure, a || b and m18 = 42. Find m25.
C. 48
D. 138
Example 1b

9. Concept

10. Concept

11. 2  3 Alternate Interior Angles Theorem
Use Theorems about Parallel Lines
FLOOR TILES The diagram represents the floor tiles in Michelle’s house. If m2 = 125, find m3.
2  3 Alternate Interior Angles Theorem
m2 = m3 Definition of congruent angles
125 = m3 Substitution
Answer: m3 = 125
Example 2

12. FLOOR TILES The diagram represents the floor tiles in Michelle’s house
FLOOR TILES The diagram represents the floor tiles in Michelle’s house. If m2 = 125, find m4.
A. 25
B. 55
C. 70
D. 125
Example 2

13. A. ALGEBRA If m5 = 2x – 10, and m7 = x + 15, find x.
Find Values of Variables
A. ALGEBRA If m5 = 2x – 10, and m7 = x + 15, find x.
5  7 Corresponding Angles Postulate
m5 = m7 Definition of congruent angles
2x – 10 = x Substitution
x – 10 = 15 Subtract x from each side.
x = 25 Add 10 to each side.
Answer: x = 25
Example 3

14. B. ALGEBRA If m4 = 4(y – 25), and m8 = 4y, find y.
Find Values of Variables
B. ALGEBRA If m4 = 4(y – 25), and m8 = 4y, find y.
8  6 Corresponding Angles Postulate
m8 = m6 Definition of congruent angles
4y = m6 Substitution
Example 3

15. m6 + m4 = 180 Supplement Theorem 4y + 4(y – 25) = 180 Substitution
Find Values of Variables
m6 + m4 = 180 Supplement Theorem
4y + 4(y – 25) = 180 Substitution
4y + 4y – 100 = 180 Distributive Property
8y = 280 Add 100 to each side.
y = 35 Divide each side by 8.
Answer: y = 35
Example 3

16. A. ALGEBRA If m1 = 9x + 6, m2 = 2(5x – 3), and m3 = 5y + 14, find x.
A. x = 9
B. x = 12
C. x = 10
D. x = 14
Example 3

17. B. ALGEBRA If m1 = 9x + 6, m2 = 2(5x – 3), and m3 = 5y + 14, find y.
A. y = 14
B. y = 20
C. y = 16
D. y = 24
Example 3

18. Concept