Geometry Terms

Front 1

Acute angle

Back 1

Measure between 0 & 90.

Front 2

Adjacent angles

Back 2

Two angles if they share a common side & no interior points.

Front 3

Angle

Back 3

The union of two (non-collinear) rays with a common end point.

Front 4

Chord

Back 4

A line segment with both endpoints on the circle.

Front 5

Circumference

Back 5

The distance along the circle beginning and ending at the same point.

Front 6

Closed

Back 6

A curve is closed if it has no endpoints.

Front 7

Collinear

Back 7

Points, segments, & rays are collinear if they lie on the same line.

Front 8

Complementary angles

Back 8

Two angles are complementary if the sum of their measures is 90.

Front 9

Congruent

Back 9

Have the same measures.

Front 10

Coplanar

Back 10

Lie in the same plane.

Front 11

Curve

Back 11

A set of points in a plane that can be traced with a pencil without lifting the pencil or retracing points.

Front 12

Decagon

Back 12

Polygon w/ 10 line segments.

Front 13

Diameter 1

Back 13

A chord that contains the center of the circle.

Front 14

Diameter 2

Back 14

The diameter of a circle is the length of a chord that contains the center.

Front 15

Dodecagon

Back 15

Polyfon w/ 12 line segments.

Front 16

Heptagon

Back 16

Polygon w/ 7 line segments

Front 17

Hexagon

Back 17

Polygon w/ 6 line segments

Front 18

Intersecting

Back 18

Geometric figures intersect if they share some points, but not all.

Front 19

Line segment

Back 19

That part of a line between two points, including the end points.

Front 20

Linear pair

Back 20

Two adjacent angles whose non-shared sides form a straight line.

Front 21

Nonagon

Back 21

Polygon w/ 9 line segments

Front 22

Obtuse angle

Back 22

Has a measurement between 90 & 180

Front 23

Octagon

Back 23

Polygon w/ 8 line segments

Front 24

Parallel lines

Back 24

Lines are parallel if they lie in the same plane and do not intersect.

Front 25

Pentagon

Back 25

Polygon w/ 5 line segments

Front 26

Perimeter

Back 26

The perimeter of a polygon is the sum of the lengths of its sides.

Front 27

Perpendicular

Back 27

Geometric shapes are perpendicular if they intersect to form right angles.

Front 28

Polygon

Back 28

A simple, closed curve consisting of consecutive line segments.

Front 29

Quadrilateral

Back 29

Polygon w/ 4 line segments

Front 30

Radius 1

Back 30

A line segment w/ one endpoint on the circle & the other endpoint being the center.

Front 31

Radius 2

Back 31

Radius of a circle is the distance from the center to a point on the circle.

Front 32

Region

Back 32

The union of the interior points of a curve and the curve itself is a region.

Front 33

Regular polygon

Back 33

A polygon w/ all 4 sides congruent & all interior angles congruent.

Front 34

Right angle

Back 34

Measures 90 degrees

Front 35

Secant

Back 35

A line that intersects a circle in two points.

Front 36

Sides of an angle

Back 36

The two rays forming ana ngle are called the sides of an angle.

Front 37

Simple

Back 37

A curve is simple if it does not intersect itself.

Front 38

Skew lines

Back 38

Lines are skew if they are not in the same plane and do not intersect.

Front 39

Supplementary angles

Back 39

Two angles that sum of their measures is 180.

Front 40

Tangent

Back 40

A line that intersects a circle in exactly one point.

Front 41

Triangle

Back 41

Polyfon w/ 3 line segments

Front 42

Undecagon

Back 42

Polygon w/ 11 line segments

Front 43

Vertex

Back 43

The common end point of two rays forming an angle.

Front 44

Vertical angles

Back 44

If two lines intersect, the two pair of non-adjacent angles are vertical angles.