25 terms

Point

an exact location in space

Line

a straight path that goes on forever in both directions

Line Segment

a piece of a line that has a beginning point and an endpoint

Ray

a line with ONE endpoint and continues on forever on one direction

Plane

a flat surface that goes on forever in all directions

Angle

2 rays with a common endpoint (vertex)

Vertex

the point where lines, rays, or edges intersect

Acute Angle

an angle that is more than 0 degrees and less than 90 degrees

Obtuse Angle

an angle that is more than 90 degees and less than 180 degrees

Right Angle

an angle that is exactly 90 degrees

Straight Angle

an angle that is 180 degrees, makes a straight line

Complementary Angles

2 angles that add up to 90 degrees

Supplementary Angles

2 angles that add up to 180 degrees

Congruent

same size and same shape

Parallel Lines

coplanar lines that do not intersect (don't get closer or farther apart)

Perpendicular Lines

coplanar lines that cross and form four 90 degree angles

Skew Lines

non-coplanar lines that do not intersect

Vertical Angles

two angles whose sides form two pairs of opposite rays

Adjacent angles

angles having a common boundary or edge (share a common ray)

Linear pair

two angles with one common side (ray), that add up to 180 degrees

Intersecting Lines

Two lines that two lines that cross one another at one common point, but do not form a 90 degree angle.

Midpoint

the point that divides (or bisects) a segment into two congruent segments

Oblique Lines

two lines that intersect and are not perpendicular

Horizontal Line

A line that runs from left to right with a slope of zero

Vertical Line

A line that runs up and down with an undefined slope