How can we help?

You can also find more resources in our Help Center.

acute angle

obtuse angle

straight angle

vertex

measures less than 90 degrees

an angle that measures greater than 90 degrees and less than…

an angle that measures 180 degrees

The common endpoint of an angle

acute angle

measures less than 90 degrees

obtuse angle

an angle that measures greater than 90 degrees and less than…

Linear Pair or supplementary

Vertical Angles

Corresponding Angles

Alternate Interior Angles

Two adjacent angles that form a straight line. The angles sum…

Two angles formed by intersecting lines that are not adjacent…

An angle pair created by a transversal where the angles lie i…

An angle pair created by a transversal where the angles lie o…

Linear Pair or supplementary

Two adjacent angles that form a straight line. The angles sum…

Vertical Angles

Two angles formed by intersecting lines that are not adjacent…

Complementary Angles

Supplementary Angles

Perpendicular Lines

Parallel Lines

angles that add up to 90 degrees, do not have to be adjacent

two angles that add up to 180 degrees, do not have to be adja…

lines that intersect and form right angles

two lines that never intersect, but are coplanar

Complementary Angles

angles that add up to 90 degrees, do not have to be adjacent

Supplementary Angles

two angles that add up to 180 degrees, do not have to be adja…

Parallel Lines

Pair of Angles

Testing on Pair of Angles

Example 1

Lines are parallel if they are always the same distance apart…

When parallel lines get crossed by another line (which is cal…

If Any Pair Of ... Example:... ... Corresponding Angles are equal,…

These lines are parallel, because a pair of Corresponding Ang…

Parallel Lines

Lines are parallel if they are always the same distance apart…

Pair of Angles

When parallel lines get crossed by another line (which is cal…

complementary angles

supplementary angles

corresponding angles

alternate interior angles

add up to 90 degrees

2 angles next to each other on a straight line

these angles "slide" along the transversal

on the inside of the parallel lines, on opposite sides of the…

complementary angles

add up to 90 degrees

supplementary angles

2 angles next to each other on a straight line

parallel lines

intersecting lines

coincident lines

skew lines

lines in the same plane that never intersect

lines that cross at exactly one point

Two lines that have all their points in common

Lines that do not intersect and are not coplanar

parallel lines

lines in the same plane that never intersect

intersecting lines

lines that cross at exactly one point

Parallel lines

skew lines

parallel planes

perpendicular plane

lines that are coplanar but do not intersect.

two lines that are not Coplanar and do not intersect

two planes that do not intersect "bookshevels"

meet at the right angle

Parallel lines

lines that are coplanar but do not intersect.

skew lines

two lines that are not Coplanar and do not intersect

you can infer a line is parallel when

a.

b.

c.

...

you can infer a line is parallel when

...

a.

Parallel Lines

Skew Lines

Parallel Planes

Parallel Postulate

Are coplanar and don't intersect (Ex: Railroad Tracks)

Not coplanar and don't intersect (Ex: Highway Overpass)

Two planes that do not intersect (Ex: Floors of a building)

If there is a line and a point not on the line, then there is…

Parallel Lines

Are coplanar and don't intersect (Ex: Railroad Tracks)

Skew Lines

Not coplanar and don't intersect (Ex: Highway Overpass)

Complementary Angles

Supplementary Angles

Perpendicular Lines

Parallel Lines

angles that add up to 90degrees, do not have to be adjacent

two angles that add up to 180degrees, do not have to be adjac…

two intersecting lines to form right angles

two lines that never intersect, but are on the same plane

Complementary Angles

angles that add up to 90degrees, do not have to be adjacent

Supplementary Angles

two angles that add up to 180degrees, do not have to be adjac…

Parallel Lines

Skew Lines

Parallel Planes

Transversal

Coplanar lines that do not intersect

Lines that do not intersect and are not coplanar

Two planes that do not intersect

a line that intersects two or more coplanar lines at differen…

Parallel Lines

Coplanar lines that do not intersect

Skew Lines

Lines that do not intersect and are not coplanar

Corresponding angles postulate

Converse of corresponding angles postu…

Alternate interior angles postulate

Converse of alternate interior angles…

If two parallel lines are cut by a transveral, then correspon…

If two lines are cut by a transversal and corresponding angle…

If two parallel lines are cut by a transversal , then alterna…

If two lines are cut by a transversal and alternate interior…

Corresponding angles postulate

If two parallel lines are cut by a transveral, then correspon…

Converse of corresponding angles postu…

If two lines are cut by a transversal and corresponding angle…

Parallel lines

||

Skew lines

Parallel planes

Two lines that do not intersect and are coplanar

Sign that means "parallel"

Two lines that do not intersect and are not coplanar

Two planes that do not intersect

Parallel lines

Two lines that do not intersect and are coplanar

||

Sign that means "parallel"

Corresponding Angles Postulate

Alternate Interior Angles Thm

Consecutive Interior Angles Thm

Alternate Exterior Angles Thm

If lines are parallel, then corresponding angles are congruen…

If lines are parallel, then alternate interior angles are con…

If lines are parallel, then consecutive interior angles are s…

If lines are parallel, then alternate exterior angles are con…

Corresponding Angles Postulate

If lines are parallel, then corresponding angles are congruen…

Alternate Interior Angles Thm

If lines are parallel, then alternate interior angles are con…

perpendicular

perpendicular bisector

adjacent angles

angle bisector

any two lines, segments, or rays that intersect at a 90 degre…

a line, segment, or ray that passes through or stops on the m…

two angles that are next to each other and share a common ray

a ray that splits an angle into two congruent angles

perpendicular

any two lines, segments, or rays that intersect at a 90 degre…

perpendicular bisector

a line, segment, or ray that passes through or stops on the m…

Parallel Lines

Perpendicular

Skew Lines

Parallel Planes

Lines that do not intersect and are on the same plane (coplan…

Lines that intersect at a right angle

Lines that do not intersect and are not on the same plane (co…

Planes that do not intersect

Parallel Lines

Lines that do not intersect and are on the same plane (coplan…

Perpendicular

Lines that intersect at a right angle

Intersecting Lines

Parallel Line

Perpendicular Lines

Skew Lines

Have only one point in common

Never touch and lie on the same plane

Intersect forming right angles

Never touch and do not lie in the same plane

Intersecting Lines

Have only one point in common

Parallel Line

Never touch and lie on the same plane

0 =

4 =

2 =

3 =

south line north line... cynwyd n/a

south line north line... air port line warminster line

south line North line... wilington/ Newark Manyunk Norristown line

south line North line... Media / elwyn line West Trenton line

0 =

south line north line... cynwyd n/a

4 =

south line north line... air port line warminster line

Parallel Lines

Skew Lines

Parallel Planes

Transversal

Two lines are parallel lines if they do not intersect and are…

Two lines are skew lines if they do not intersect and are not…

Two planes that do not intersect are parallel planes

A transversal is a line that intersects two or more coplanar…

Parallel Lines

Two lines are parallel lines if they do not intersect and are…

Skew Lines

Two lines are skew lines if they do not intersect and are not…

you can infer a line is parallel when

a.

b.

c.

...

you can infer a line is parallel when

...

a.

Parallel Lines

Parallel Planes

Skew Lines

Perpendicular Lines

Coplanar lines that do not intersect

Planes that do not intersect

Lines that do not intersect and are not coplanar (not parallel)

Lines that intersect at a right angle

Parallel Lines

Coplanar lines that do not intersect

Parallel Planes

Planes that do not intersect

parallel

perpendicular

skew

transversal

coplanar lines that never intersect

lines that intersect at a 90 degree angle

non coplanar lines that never intersect

a line that intersects two or more lines

parallel

coplanar lines that never intersect

perpendicular

lines that intersect at a 90 degree angle

Parallel lines

Skew lines

Coincident lines

Parallel planes

Coplanar lines that do not intersect

Non Coplanar lines that do not intersect

Two lines that lie exactly on top of each other

Two planes that do not intersect

Parallel lines

Coplanar lines that do not intersect

Skew lines

Non Coplanar lines that do not intersect

complementary angles CAP

supplementary angles

linear pair LP

vertical angles VA

2 angles that add to 90°.

2 angles that add to 180º.

2 angles that are adjacent and add to 180º.

2 angles formed opposite of each other when two lines interse…

complementary angles CAP

2 angles that add to 90°.

supplementary angles

2 angles that add to 180º.