35 terms

# Geometry

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point
This marks and exact location in space.
line
An endless straight path. Has no end points
ray
Part of line that goes on forever in one direction. Has one end point.
line segment
Part of a line between two end points.
plane
An endless flat surgace. Named by three points.
angle
Formed by two rays with the same endpoint (vertex).
right angle
An angle that measures 90 degrees.
acute angle
An angle that measures less than 90 degrees.
obtuse angle
An angle that measures more than 90 degress.
straight angle
An angle that measures 180 degrees.
parallel lines
Lines, in the same plane, that never intersect.
Intersecting lines
Lines that cross at one point.
perpendicular lines
Lines that intersect at right angles.
polygon
A closed, plane (flat) figure, formed by three or more line segments.
regular polygon
A polygon that has sides of equal measure, and has angles of equal measure.
Triangle
3 sides, 3 angles
4 sides, 4 angles
pentagon
5 sides, 5 angles
hexagon
6 sides, 6 angles
octagon
8 sides, 8 angles
Congruent
Figures that have the same size and shape.
Similar
Figures that have the same shape, but different sizes.
Line of Symmetry
A line that divides a figure into two congruent parts.
Angles of a Triangle
Polyhedron
A solid figure with faces that are polygons.
prism
A polyhedron that has two congruent (exactly the same) bases.
pyramid
A polyhedron with only one base.
Edge
Line where two faces come together.
Faces
The flat surfaces of solid figures
Vertex (plural - verteces)
The point where several edges come together.
Transformation
Movement of a figure that does not change it's size or shape.
translation
Sliding of a figure in a straight line. The figure does not change direction.
hudjw
Flipping a figure over a line (mirror). Figure is now in the opposite direction.
Rotation
Turning a figure around a point (vertex). Placing your finger on one corner of the figure, and turing the object around your finger.