###
Angle

Formed by two rays that have the same endpoint

###
Vertex

Where two endpoints meet

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Interior

Inside of an angle

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Exterior

Outside of an angle

###
Acute Angle

Less than 90 degrees

###
Obtuse Angle

More than 90 degrees

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Right Angle

Exactly 90 degrees

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Straight angle

Exactly 180 degrees

###
Diameter

Connects from one side to another

###
Radius

Connects from one side to the center

###
Chord

Any line segment that connects to two point

###
Central Angle

An Angle whose vertex is in the center

###
Polygon

A closed plain figure

###
Regular Polygon

A polygon with equal sides in length

###
Triangle

A polygon with three sides

###
Eqaulateral Triangle

A triangle with all sides the same length

###
Isosoeles Triangle

A triangle with only two sides the same length

###
Scalene Triangle

of a triangle having three sides of different lengths

###
Right Triangle

A triangle with one right angle

###
Acute Triangle

A triangle that has three acute angles

###
Obtuse Triangle

A triangle with one obtuse angle

###
Quadrilateral

a four-sided polygon

###
Pentagon

A five-sided polygon

###
Hexagon

A six-sided polygon

###
Octagon

An eight-sided polygon

###
Parallelogram

A quadrilateral whose opposite sides are both parallel and equal in length

###
Rectangle

A quadrilateral with four right angles

###
Square

A rectangle with all sides the same length

###
Rhombus

A parallelogram with all sides same length

###
Trapazoid

Quadrilateral with one pair of opposite sides parallel

###
Similar Figures

Figures that have the same shape but not necessarily the same size

###
Congruent Figures

Figures that have the same size and shape

###
Point

An exact spot on a line or dot

###
Line

A straight mark that never ends

###
Ray

A straight line extending from a point

###
Perpendicular Lines

Lines that intersect to form right angles

###
Intersecting Lines

Lines that meet but don't form right angles

###
Parallel

Two lines that will never intersect

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