1. Parallel Lines & Transversals

2. Lessons 3.3 Angles formed by Transversals
You will learn to…
* identify angles formed by
transversals

3. transversal – a line that intersects two or more coplanar lines at different pointsno
transversal

4. Occupy corresponding positions
corresponding angles 1 2 3 4 6 5 7 8 2 5 1 6 4 8 3 7
Occupy corresponding positions

5. alternate interior angles
Lie between two lines
on opposite sides

6. alternate exterior angles2 7 2 7 1 8 1 8 4 3 6 5
Lie outside two lines
on opposite sides of transversal

7. same-side interior angles1 2 3 4 6 5 4 3 6 5 7 8
Lie between two lines
on same side of transversal

8. A line, ray, or segment that intersects 2 or more COPLANAR lines, rays, or segments.
transversal
transversal
Parallel lines
Non-Parallel lines
Transversal

9. INTERIOR –The space INSIDE the 2 lines
EXTERIOR The space OUTSIDE the 2 lines
exterior

10. Special Angle Relationships
Interior Angles
<3 & <6 are Alternate Interior angles
<4 & <5 are Alternate Interior angles
<3 & <5 are Same Side Interior angles
<4 & <6 are Same Side Interior angles 1 4 2 6 5 7 8 3
Exterior Angles
<1 & <8 are Alternate Exterior angles
<2 & <7 are Alternate Exterior angles
<1 & <7 are Same Side Exterior angles
<2 & <8 are Same Side Exterior angles
Special Angle Relationships

11. Special Angle Relationships WHEN THE LINES ARE PARALLEL
♥Alternate Interior Angles are CONGRUENT ♥Alternate Exterior Angles are CONGRUENT ♥Same Side Interior Angles are SUPPLEMENTARY ♥Same Side Exterior Angles are SUPPLEMENTARY 1 4 2 6 5 7 8 3
If the lines are not parallel, these angle relationships DO NOT EXIST.

12. Let’s Practice m<1=120° Find all the remaining angle measures. 1 46 5 7 8 3
m<1=120° Find all the remaining angle measures.
120°
60°
120°
60°
120°
60°
120°
60°
Let’s Practice

13. Another practice problem
40°
Find all the missing angle measures, and name the postulate or theorem that gives us permission to make our statements.
120°
Another practice problem

14. Assignment
Pg 160, A & B