1. LINEAR ANGLES
August 15th
Assessment day!
August 16th
Learning outcome:
How do we use deductive reasoning to
proficiently justify geometric properties?

2. WARM – UP LINEAR ANGLES FORMED BY
PARALLEL LINES
1.If two parallel lines are
intersected by a transversal,
what relations exist among
the measures of the angles
formed?
a. If < 1 = 110° Find the
measures of all the other
angles.

3. LABELLING ANGLES

4. TOOLKIT
Justifcation
Statement
Definition OR
If-Then
Statement
Picture Relationship
(Congruent OR
Supplementar
y)
Check when
ready to be
used in a proof
Definition of
Linear Pair
Definition of
Vertical Angles
Linear Pair
Postulate
Vertical Angle
Theorem

5. TOOLKIT
Justifcation
Statement
Definition OR
If-Then
Statement
Picture Relationship
(Congruent OR
Supplementar
y)
Check when
ready to be
used in a proof
Definition of
Corresponding
Angles
Definition of
Alternate
Interior Angles
Definition of
Alternate
Exterior Angles
Definition of
Same-Side
Interior Angles
Definition of
Same-Side

6. TOOLKIT
Justification
Statement
Definition OR
If-Then
Statement
Picture Relationship
(Congruent OR
Supplementar
y)
Check when
ready to be
used in a proof
Corresponding
Angle
Assumption
Alternate
Interior Angle
Postulate
Alternate
Exterior Angle
Postulate
Same-Side
Interior Angle
Postulate
Same-Side
Exterior Angle

7. EXPLORE - PAGE 36 #4
Given
Linear Pair Postulate
Corresponding Angles
Substitution
Definition of Supplementary
If two parallel lines are cut by a transversal, then
__________________ angles are _____________________.
Vertical Angle Theorem

8. TOOLKIT
Justifcation
Statement
Definition OR
If-Then
Statement
Picture Relationship
(Congruent OR
Supplementar
y)
Check when
ready to be
used in a proof
Corresponding
Angle
Assumption
Alternate
Interior Angle
Postulate
Alternate
Exterior Angle
Postulate
Same-Side
Interior Angle
Postulate
Same-Side
Exterior Angle

9. EXPLORE - PAGE 37 #5
 If two parallel lines are cut by a transversal, then same-side
exterior angles are ________________.
 If two parallel lines are cut by a transversal, then alternate
interior angles are _________________.
 If two parallel lines are cut by a transversal, then alternate
exterior angles are _________________.
Given
Linear Pair Postulate Corresponding Angles Assumption
Substitution
Definition of Supplementary
Vertical Angle Theorem

10. SUMMARY - GALLERY WALK
 Were the requirements of a proficient proof met?
 Does the argument have any errors?
 Does it show the statement is true for all numbers or for some
numbers?
 Does the argument show why the statement is true?
 Does the argument provide an easy way to convince a skeptic?
 Return to your proof and read your feedback.
 Write a final draft of your proof.

11. TOOLKIT
Justifcation
Statement
Definition OR
If-Then
Statement
Picture Relationship
(Congruent OR
Supplementar
y)
Check when
ready to be
used in a proof
Corresponding
Angles
Postulate
Alternate
Interior Angles
Postulate
Alternate
Exterior Angles
Postulate
Same-Side
Interior Angles
Postulate
Same-Side
Exterior

12. CLASSWORK – P. 32-33 #3 C

13. CLASSWORK – P. 32-33 #3 C

14. SUMMARY
PREPARE FOR QUIZ
p. 15
1. Summarize the mathematics
2. Check your understanding