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point

This marks and exact location in space.

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line

An endless straight path. Has no end points

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ray

Part of line that goes on forever in one direction. Has one end point.

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line segment

Part of a line between two end points.

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plane

An endless flat surgace. Named by three points.

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angle

Formed by two rays with the same endpoint (vertex).

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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 than 90 degress.

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straight angle

An angle that measures 180 degrees.

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parallel lines

Lines, in the same plane, that never intersect.

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Intersecting lines

Lines that cross at one point.

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perpendicular lines

Lines that intersect at right angles.

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polygon

A closed, plane (flat) figure, formed by three or more line segments.

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regular polygon

A polygon that has sides of equal measure, and has angles of equal measure.

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Triangle

3 sides, 3 angles

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Quadrilateral

4 sides, 4 angles

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pentagon

5 sides, 5 angles

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hexagon

6 sides, 6 angles

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octagon

8 sides, 8 angles

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Congruent

Figures that have the same size and shape.

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Similar

Figures that have the same shape, but different sizes.

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Line of Symmetry

A line that divides a figure into two congruent parts.

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Angles of a Triangle

Add up to 180 degrees.

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Angles of a Quadrilateral

Add up to 360 degrees.

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Polyhedron

A solid figure with faces that are polygons.

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prism

A polyhedron that has two congruent (exactly the same) bases.

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pyramid

A polyhedron with only one base.

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Edge

Line where two faces come together.

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Faces

The flat surfaces of solid figures

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Vertex (plural - verteces)

The point where several edges come together.

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Transformation

Movement of a figure that does not change it's size or shape.

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translation

Sliding of a figure in a straight line. The figure does not change direction.

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hudjw

Flipping a figure over a line (mirror). Figure is now in the opposite direction.

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Rotation

Turning a figure around a point (vertex). Placing your finger on one corner of the figure, and turing the object around your finger.

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