Relationships Between Lines

1
Relationships Between Lines
Parallel Lines two lines that are coplanar and
do not intersect Skew Lines two lines that
are NOT coplanar and do not intersect Perpendicul
ar Lines two lines that intersect to form a
right angle Parallel Planes two planes that do
not intersect
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Parallel and Perpendicular Postulates
P

• Postulate 13 Parallel Postulate
• If there is a line and a point not on the line,
  then there is exactly one line through the point
  parallel to the given line.
• Postulate 14 Perpendicular Postulate
• If there is a line and a point not on the line,
  then there is exactly one line through the point
  perpendicular to the given point.

l
P
l
3
Transversals

• A transversal is a line that intersects two or
  more coplanar lines at different points.

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Angles Formed By Transversals
Corresponding Angles two angles are
corresponding if they occupy corresponding
positions as a result of the intersection of the
lines. (1 5) Alternate Exterior Angles two
angles are alternate exterior if they lie outside
the two lines on opposite sides of the
transversal (1 7) Alternate Interior Angles
Two angles that lie between the two lines on
opposite sides of the transversal (4
6) Consecutive Interior Angles two angles that
lie between the two lines on the same side of the
transversal (4 5)
Who can name another pair for each of the angle
types above?