GeometrySmallLogo

Definitions of Parallel & Perpendicular
MathBitsNotebook.com

Topical Outline | Geometry Outline | MathBits' Teacher Resources

Terms of Use   Contact Person: Donna Roberts
divider

refresher

def
Two lines are parallel if and only if they lie in the same plane and do not intersect. Parallel lines never cross.

Parallel lines are always the same distance apart, which is referred to as being "equidistant".
For our purposes, parallel lines will always be straight lines that go on indefinitely.
The parallel lines may be horizontal, vertical or slanted.

parallellines
monsterpoint

Parallel lines are marked with "feathers" (arrows) such as > or >>.
The notation to indicate parallel lines are two vertical bars | |.
Line m being parallel to line n is written m | | n.

Segments and rays may also be described as being parallel
when the lines containing these segments or rays are also parallel.

dividerdash


def
A transversal is a line that intersects two or more lines in the same plane. The intersected lines may, or may not, be parallel.

When lines intersect, a series of angles are formed. Certain angles are given specific "names" based upon their locations in relation to the lines. These specific names may be used whether the lines involved are parallel or not parallel.

notparallel
purplemonster
yesparallel

Each diagram above shows eight angles formed by the transversal and the two intersected lines. The term "INTERIOR" refers to the space "between" the two intersecting lines, while the term "EXTERIOR" refers to the spaces that are not between the intersecting lines (i.e. the outer regions).

dividerdash

def
Two lines are perpendicular if and only if they form a right angle.

Perpendicular lines always form a right angle of 90ยบ.
While perpendicular lines may appear in a slanted or a horizontal position on paper,
the lines must always intersect to form a right angle.

perpslanted
(slanted position)
perphoriz
(horizontal position)

Perpendicular lines are marked with a "square" (a box) drawn at the point of intersection.
The notation to indicate perpendicular lines is ⊥.
Line m being perpendicular n is written mn.

Segments and rays may also be described as being perpendicular
when the lines containing these segments or rays are also perpendicular.


divider


NOTE: The re-posting of materials (in part or whole) from this site to the Internet is copyright violation
and is not considered "fair use" for educators. Please read the "Terms of Use".