This geometry lesson discusses parallel lines and how to prove they are parallel using angle properties such as corresponding angles, alternate interior angles, and consecutive interior angles. It includes examples of parallel line problems and checkpoints for students to practice identifying parallel lines using angle measures. The document provides guided practice problems for students to determine if lines are parallel.

1. MR. SAUCEDO
GEOMETRY
MILBY HIGH SCHOOL
3.3 Prove that lines are parallel

2. REVIEW
FOLDABLE ACTIVITY
You will neeed:
 Foldable sheet
 Color pencils

3. CORRESPONDING ANGLES
FACTS:
•They are congruent
•They slide down and up in the same position.

4. ALTERNATE INTERIOR ANGLES
FACTS
 They are congruent

5. ALTERNATE EXTERIOR ANGLES
FACTS
 They are congruent.

6. CONSECUTIVE INTERIOR ANGLES
FACTS:
 THEY ADD UP TO 180 DEGREES.

7. OTHER
REMINDERS
Parallel
Perpendicular
Supplementary
Complementary

8. CHECKPOINT
Angle 2 and 4 are congruent.
SMART Response Que
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9. CHECKPOINT
Angles P and Q are corresponding angles.
SMART Response Ques
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10. Angles R and K are Alternate interior
SMART Response Ques
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11. CHECKPOINT
If angle R is 70 degrees, then angle Q is 110 degrees.
SMART Response Ques
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12. BIG QUESTION
If <4≈<3, can we say that lines e and f are parallel?
SMART Response Ques
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13. QUESTION
If m<H=110, what does angle M need to be so that
line Q ll R?
If m<K=30, what
does angle O need
to be so that
line Q ll R?

14. CHECKPOINT
If m<O=100, what does m<J have to be in order that
Q ll R.
SMART Response Question
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15. GUIDED PROBLEM
Are lines AB and CD parallel?
SMART Response Question
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16. QUESTION
If m<3 ≈ m<5, are lines DK and GH parallel?
SMART Response Que
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17. GUIDED PROBLEM
What does x have to be so that lines l and m be
parallel?

18. CHECKPOINT
What does x have to be so that lines AB and CD be
parallel?
SMART Response Question
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SMART Response Question Object->Properties...

19. MORE PRACTICE
WORK PROBLEMS:
Page 159: problems 27, 29, 31 & 38.
Page 165: problems 4, 6, 8, 10, 14.