Geometry: Chapter 1 Vocabulary Cards

Front 1

Collinear

Back 1

Points that lie on the same line.

Front 2

Coplanar

Back 2

Points that lie on the same plane

Front 3

Endpoint

Back 3

A point at the end of a segment or the starting point of a ray.

Front 4

Line

Back 4

A straight path that has no thickness and extends forever.

Front 5

Opposite Rays

Back 5

Two rays that have a common end point a form a line.

Front 6

Plane

Back 6

A flat surface that has no thickness and extends forever.

Front 7

Point

Back 7

It names a location and has not size.

Front 8

Postulate (axiom)

Back 8

A statement that is accepted as true without proof.

Front 9

Ray

Back 9

A part of a line that starts at an endpoint and extends forever in one direction.

Front 10

Segment

Back 10

A part of a line consisting of two end points.

Front 11

Undefined Terms

Back 11

A basic figure that is not defined in terms of other figures.

The undefined terms in geometry are:
1. Point
2. Line
3. Plane

Front 12

Congruent Segments

Back 12

Two segments that have the same length.

Front 13

Construction

Back 13

A method of creating a figure that is considered mathematically precise.

Front 14

Coordinate

Back 14

A number used to identify the location of a point.

Front 15

Distance

Back 15

The absolute value of the difference of the coordinates of the points.

Front 16

Length

Back 16

The distance between to end points of a segment.

Front 17

Midpoint

Back 17

The point that divide a segment into two congruent segments.

Front 18

Segment Bisector

Back 18

A ray, line, or segment that divides a segment into two congruent segments.

Front 19

Acute Angle

Back 19

An angle that measures greater than 0 degrees but less than 90 degrees.

Front 20

Angle

Back 20

A figure formed by two rays with a common endpoint.

Front 21

Angle Bisector

Back 21

A ray that divides an angle into two congruent angles.

Front 22

Bisect

Back 22

To divide into two congruent parts.

Front 23

Congruent Angles

Back 23

Angles that have the same measure.

Front 24

Degree

Back 24

A unit of angle measure; one degree is 1/360 of a circle.

Front 25

Exterior of an Angle

Back 25

The set of all points outside an angle.

Front 26

Interior of an Angle

Back 26

The set of all points between the sides of an angle.

Front 27

Obtuse Angle

Back 27

An angle that measures greater than 90 degrees and less than 180 degrees.

Front 28

Right Angle

Back 28

An angle that measures 90 degrees.

Front 29

Straight Angle

Back 29

An angle that measures 180 degrees.

Front 30

Vertex of an angle

Back 30

The common endpoint of the sides of the angle.

Front 31

Adjacent Angles

Back 31

Two angles in the same plane with a common vertex and common side but no common interior parts.

Front 32

Complementary Angles

Back 32

Two angles whose measures have a sum of 90 degrees.

Front 33

Linear Pair

Back 33

A pair of adjacent angles whose non common sides are opposite rays.

Front 34

Supplementary Angles

Back 34

Two angles whose measures have a sum of 180 degrees.

Front 35

Vertical Angles

Back 35

The nonadjacent angles formed by two intersecting lines.