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point

an exact location in space

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line

an infinite set of points forming a straight path extending in opposite directions

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line segment

a part of a line that consists of the two endpoints and all the points of the line between them

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ray

a part of a line that has one endpoint and extends infinitely in one direction

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midpoint

the point on a line segment that divides it into two equal segments

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angle

the union of two rays that share a common endpoint

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plane

a flat surface with infinite lengthe and width but no thickness

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collinear

on the same line

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perpindicular lines

lines that intersect to form a right angle

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parallel lines

lines in the same plane that do not intersect

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supplementary angles

two angles with measures whose sum is 180 degrees

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interior angle

An angle on the inside of a polygon, formed by the sides of the polygon (see GSP3

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Exterior angle

: An angle formed by the side of a polygon and an extension of an adjacent side. At each vertex, there are two exterior angles (see GSP3

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Adjacent angles

Angles that share a common ray and endpoint, but that do not overlap

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Linear pair

A linear pair of angles is formed when two lines intersect. The angles are adjacent and formed by the two intersecting lines. Below, and are a linear pair

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vertex

The common endpoint of two rays or segments (plural: vertices)

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Polygon

A closed figure formed by line segments that meet only at their endpoints

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Regular polygon

A polygon that has all sides congruent and all angles congruent.

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Triangle

A three-sided polygon

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Quadrilateral

A four-sided polygon

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Pentagon

A five-sided polygon

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Hexagon

A six-sided polygon

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Septagon

A seven-sided polygon

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Octagon

An eight-sided polygon

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Nonagon

A nine-sided polygon

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Decagon

A ten-sided polygon

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Interior angle

An angle on the inside of a polygon, formed by the sides of the polygon (see GSP 3

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Exterior angle

An angle formed by the side of a polygon and an extension of an adjacent side. (see GSP

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Linear pairs are supplementary

Linear pairs are supplementary

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The sum of the interior angles of a convex polygon with n sides is 180(n - 2)0

The sum of the interior angles of a convex polygon with n sides is 180(n - 2)0

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The sum of the exterior angles of all convex polygons is 3600

The sum of the exterior angles of all convex polygons is 3600

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