1. 3.1 Pairs of Lines and Angles

2. What We Will Learn Identify lines and planes
Identify parallel and perpendicular lines
Identify pairs of angles formed by transversals

3. Needed Vocab
Parallel lines: lines that are coplanar and do not intersect
Skew lines: lines that are not coplanar and do not intersect
Parallel planes: planes that do not intersect
Transversal: line that intersects two or more coplanar lines at different points
Corresponding angles: angles that are on same side of transversal and the coplanar lines
Alternate interior angles: angles between coplanar lines and on opposite sides of the transversal
Alternate exterior angles: angles outside the coplanar lines and on opposite sides of the transversal
Consecutive (same side) interior angles: angles between coplanar lines and on same side of transversal

4. Ex. 1 Identifying Lines and Planes
A. line(s) parallel to 𝐶𝐷 containing point A 𝐴𝐵
B. plane parallel to EFG containing point A
Plane ABC
C. line(s) perpendicular to 𝐴𝐷
𝐸𝐷 , 𝐶𝐷 , 𝐻𝐴 , 𝐴𝐵
D. name 2 skew lines
𝐴𝐷 , 𝐻𝐺 C B A D F G E H

5. Ex. 2 Identify Parallel and Perpendicular Lines
∥𝑚𝑒𝑎𝑛𝑠 𝑝𝑎𝑟𝑎𝑙𝑙𝑒𝑙
⊥𝑚𝑒𝑎𝑛𝑠 𝑝𝑒𝑟𝑝𝑒𝑛𝑑𝑖𝑐𝑢𝑙𝑎𝑟
Name a pair of ∥ lines
𝐷𝑀 , 𝐸𝐹
Name a pair of ⊥ lines
𝐵𝐹 , 𝐴𝐷

6. Ex. 3 Identifying Angles Name: A. corresponding angles
∠1, ∠5; ∠2, ∠6; ∠3, ∠7; ∠4, ∠8
B. alternate interior
∠2, ∠7; ∠4, ∠5
C. alternate exterior
∠1, ∠8; ∠3, ∠6
D. consecutive (same side)
∠2, ∠5; ∠4, ∠7