Term

Definition
A point has no size, but marks itself in space.  It is represented by a small dot, and it is labeled with a capital letter.



Term

Definition
A line extends in opposite directions without end. It has no width, and it cannot be measured.  It is represented by a straight line with an arrow on each end, and it is labeled using the names of two points on the line. It can also be labeled with one lowercase cursive letter.



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Definition
A flat surface that extends out in all directions. It is represented by a flattened rectangle shape. A place cannot be measured.  It is labeled with 3 points that are not in a straight line. A plane can also be labeled with a capital script letter written in a corner.



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Definition
Space is the air around us. It is the place where everything exists. Space cannot be measured.  There is no specific notation for space.



Term

Definition
A line segment has length, but no width. It it considered to be part of a line between two points. The distance between the two points is considered the legth of the line segment.  A line is named with the two endpoints and a line over them. The lenght of the line is notated using just the two endpoints.



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Definition
A ray has no length and is sometimes thought of as half of a line. It has one endpoint and continues in one direction endlessly.  A ray is named using the endpoint first and another point that the ray passes through.



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Definition
The set of points two or more geometric figures have in common.  If two figures have just one point in common, then that point is called the point of intersetion.



Term

Definition
Parallel lines lie the same distance between from each other. These lines never intersect. 


Term

Definition
Perpendicular lines meet each other at a right angle. 


Term

Definition
Skew lines are lines that are not in the same place and never intersect. 


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Definition
The midpoint of a segment is the point that is the same distance from each endpoint. 


Term

Definition
If a figure is bisected, then it is cut into two pieces that are equal in size. 


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Definition
An angle whose measure is between 0 and 90 degrees. 


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Definition
An angle whose measure is exactly 90 degrees. 


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Definition
An angle whose measure is between 90 and 180 degrees. 


Term

Definition
An angle whose measure is exactly 180 degrees. 


Term

Definition
A pair of angles that share a vertex and a side. * The term adjacent means "side by side." 


Term

Definition
Angles whose measures add up to 90 degrees. * These angles make a right angle. 


Term

Definition
Angles that add up to 180 degrees. 


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Definition
A Linear pair is created by two angles that are adjacent and supplementary. 


Term

Definition
Vertical Angles are formed when two lines intersect. These angles are congruent; they are equal to each other. 


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Definition
A polygon is a simple closed figure. It is made up of line segments and never contains curved lines. 


Term

Definition
A polygon where the line connecting any two points inside the polygon lies wholly inside the polygon. 


Term

Definition
A polygon where the line connecting any two points inside the polygon will go outside of the polygon. * Concave polygon "caves in" at some point. 


Term
Polygons: Triangle; Quadrilateral; Pentagon; Hexagon; Heptagon; Octagon; Nonagon; Decagon or Decahedron; Dodecagon; ngon. 

Definition
 Triangle  3 sides
 Quadrilateral  4 sides
 Pentagon  5 sides
 Hexagon  6 sides
 Heptagon  7 sides
 Octagon  8 sides
 Nonagon  9 sides
 Decagon or Decahedron  10 sides
 Dodecagon  12 sides
 Ngon  "n" sides



Term

Definition
All of the sides have equal length and all of the interior angles have equal measure. 


Term

Definition
The vertices* of a polygon are the points on the corners where two line segments come togehter. * Plural form of "vertex" 


Term

Definition
The distance from the center of the polygon to the vertex. 


Term

Definition
The distance from the center of a regular polygon to the midpoint of the side of the polygon. * It must also be perpendicular to the side of the polygon. 


Term

Definition
All three sides of the triangles are equal lengths. 


Term

Definition
Two of the sides are equal in length. 


Term

Definition
None of the sides are the same length. 


Term

Definition
All three angles are the same size. 


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Definition
All three angles have measures less than 90 degrees. 


Term

Definition
One angle measures greater than 90 degrees. 


Term

Definition
One angle measures 90 degrees. 


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Definition
A quadrilateral with 2 pairs of adjacent sides congruent. 


Term

Definition
A quadrilateral with 2 pair of parallel sides and 2 pair of congruent sides. 


Term

Definition
A quadrilateral with one pair of parallel side. 


Term

Definition
A parallelogram with 4 right angles. 


Term

Definition
A Parallelogram with 4 congruent sides. 


Term

Definition
A trapezoid with congruent nonparallel sides. 


Term

Definition
A parallelogram that has congruent sides and four right angles. 


Term

Definition
The set of points in a plane that are equidistant from one point. 


Term

Definition
The distance from the center of the circle to the edge of the circle. 


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Definition
A segment from one edge of the circle to the other edge anywhere on the circle. 


Term

Definition
A central angle is made using two radii (plural form of radius) of the circle. It is an angle with its vertex on the center of the circle. 


Term

Definition
Minor Arcs extend less than half way around the circle. 


Term

Definition
Major Arcs extend more than half way around a circle. 


Term

Definition
Semicircle extend exactly halfway around a circle. It measures 180 degrees. 


Term

Definition
Congruent figures are figures that are the same size and shape. 


Term

Definition
A congruence statement is a statement about different sides, angles, or figures that are congruent. * Example: Triangle ABC is congruent or equal to Triangle DEF. 

