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point

has no size, only location

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line

straight, continous arrangement of infinitely many points; has no thickness; one-dimensional

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plane

flat surface; two-dimensional; surface extends indinitely along its length and width; a plane is named with script capital letter

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collinear

points that lie along the same line

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coplainar

points that lie within the same plane

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line segment

consists of two points called the endpoints of the segment and all the points between them that are collinear with the two points

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congruent segments

segments that are equal in measure or length

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midpoint

the point on the segment that is the same distance from both endpoints. A pair of hatch marks refer to line segments being the same length

###
ray

begins at a point and extends infinitely in one direction

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angle

formed by two rays that share a common endpoint

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vertex

the common endpoint of the two rays of the angle

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sides

the rays of an angle

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measure of an angle

the smallest amount of rotation about the vertex from one ray to the other

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degrees

unit of measurement for an angle

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protractor

a geometry tool used to measure angles

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congruent angles-

angles that are equal in measure

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angle bisector

a ray that divides the angle into two congruent angles

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parallel lines

lines that do not intersect and are part of the same plane

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perpendicular lines

lines that do intersect and form a right angle

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skew lines

lines that are neither parallel nor do they intersect (for 3-D setting)

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right angle

an angle that measures 90 degrees

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acute angle

an angle that measures less than 90 degrees

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obtuse angle

an angle that measures more that 90 degrees

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pair of vertical angles

angles that are formed by two intersecting lines; they share a common vertex but not a common side

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linear pair of angles

two angles are a ____if they share a vertex and a common side and their non-common sides form a line

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complementary angles

angles that form a right angle

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supplementary angles

angles that sum up to 180 degrees

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polygon

closed figure in a plane, formed by connecting line segments endpoint to endpoint with each segment intersecting the other

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consecutive vertices

vertices that are adjacent to one another

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consecutive angles

angles that are adjacent to one another

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diangonal

a line segment that connects any two nonconsecutive vertices

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concave polygon

a polygon that has at least one diagonal on the outside

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convex polygon

a polygon that has no diagonals on the outside

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congruent polygons

polygons that have exactly the same size and shape

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equilateral polygons

a polygon who's sides are all equal

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equilangular polygon

a polygon whose angles are all equal

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regular polygon

a polygon whose sides and angles are all equal

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icosakaihenadecagon

21 sides

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chiliagon

1000 sides (chilagon?)

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acute triangle

all angles are less than 90 degrees

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obtuse triangle

one angle is more than 90 degrees and less than 180 degrees of a three sided polygon

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right triangle

one angle is exactly 90 degrees

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scalene triangle

no two sides are congruent of a three sided polygon

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isosceles triangle

at least two sides are congruent of a three sided polygon

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equilateral triangle

all sides are congruent of a three sided polygon

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trapazoid

a quadrilateral with exactly one pair of parallel sides

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isosceles trapazoid

top and bottom are parallel, two sides are congruent, top two angles are congruent, bottom two angles are congruent

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right trapazoid

two right angles

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kite

a quadrilateral with two pairs of consecutive congruent sides. The diagonails are perpendicular

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parallelogram

a quadrilateral with two pairs of parallel sides

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rhombus

an equilateral parallelogram

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rectangle

a parallelogram with four congruent angles (right angles); an equilateral parallelogram

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square

an equilateral, equilangular parallelogram; a regular quadrilateral; an equalateral rectangle

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circle

a set of all points in a plane that are the same distance from a given point (center) in a plane

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radius

a line segment from the center point of a circle to a point on the edge of a circle

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diameter

a line segment passing through the center point of a circle and whose endpoints are on the edge of the circle

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chord

any line segment whose endpoints are on the edge of a circle; the diameter is the longest chord

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congruent circles

circles that have the same radius length

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concentric circles

circles that share the same center point

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arc of a circle

the continuous (unbroken) part of a circle that is in between two points on the edge of a circle

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semicircle

arc of a circle whose endpoints are the endpoints of the diameter

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minor arc

an arc of a circle that is smaller than a semicircle

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major arc

an arc of a circle that is larger than a semicircle

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arc measure

the measure of the central angle (in degrees)

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central angle

angle formed by two radii and whose vertex is the center point of a circle

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tangent

a line that intersects the circle at exactly one point

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secant

a line that intersects the circle at exactly two points

###
inscribe angle

angle whose vertex is the point on a circle; the sides of this angle are the chords of the circle

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