3-1 Lines and AnglesBoyd/Usilton

Parallel and Skew LinesParallel lines:

coplanar lines that do not intersect.

Skew lines: are noncoplanar, not parallel and do not intersect.

Parallel planes: planes that do not intersect.

B C

A

F

D E

Angle Pairs Formed by TransversalsAlternate interior:

nonadjacent interior angles that lie on opposite sides of the transversal.

Same-side interior: interior angles that lie on the same side of the transversal.

Angle Pairs Formed by TransversalsCorresponding: lie

on the same side of the transversal and in corresponding positions.

Alternate-interior: nonadjacent exterior angles that lie on opposite sides of the transversal.