Download 3.1 Pairs of Lines and Angles

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Notes 3.1 & 3.2
Parallel lines, angles, transversals
3.1 Pairs of Lines and Angles
Term
Parallel Lines
Definition
Two lines are parallel lines if they …
Skew Lines
Two lines are skew if they…
Parallel Planes
Two planes are parallel if they …
Transversal
A transversal is a line that…
Perpendicular Lines
Two lines that intersect…
Parallel Postulate
Diagram
If there is a line and a point not on the line, then
there is _______________________ line through
the point parallel to the given line.
There is exactly one line through P parallel to  .
Perpendicular
Postulate
If there is a line and a point not on that line, then
there is _________________________
line through the point perpendicular to the given line.
There is exactly one line through P perpendicular to  .
G13B
Think of each segment in the diagram as part of a line. Complete
the statement with parallel, skew, or perpendicular.




WZ and ZR are__________WZ and ST are___________


QT and YS are__________
Plane WZR and plane SYZ are___________________________
Think of each segment in the diagram as part of a line.
Which line(s) or plane(s) appear to fit the description?

Line(s) parallel to EH

Line(s) perpendicular to EH

Line(s) skew to CD and containing point F
Plane(s) perpendicular to plane AEH
Plane(s) parallel to plane FGC
Angles formed by a transversal (t)
Two angles are ___________________________
angles if they have corresponding potions. For example ∠2
and ∠6 are above the lines and to the right of the
transversal t.
Two angles are ____________________________
angles if they line between the two lines and on opposite
sides of the transversal.
Two angles are _____________________________
angles if they line outside the two lines and on opposite
sides of the transversal.
Two angles are _______________________________
angles if they line between the two lines and on the same
side of the transversal.
Classify the angle pair as corresponding,
alternate interior, alternate exterior, or
consecutive interior angles.
List all possible correct answers.
∠2 and __?__ are corresponding angles.
∠4 and __?__ are consecutive interior angles.
∠l1 and __?__ are alternate interior angles.
∠12 and __?__ are alternate exterior angles.
∠l and ∠5
∠11 and ∠16
∠4 and ∠6
∠16 and ∠10
∠12 and ∠14
∠7 and ∠13
3.2 Parallel lines and Transversals
Corresponding
Angles Postulate
If two parallel lines are cut by a transversal,
then the pairs of corresponding angles are
congruent.
Alternate Interior
Angle Theorem
If two parallel lines are cut by a transversal,
then the pairs of alternate interior angles are
congruent.
Alternate Exterior
Angles Theorem
If two parallel lines are cut by a transversal,
then the pairs of alternate exterior angles
are congruent.
Consecutive Interior
Angle Theorem
If two parallel lines are cut by a transversal,
then the pairs of consecutive interior angles
are supplementary.