# GEOMETRY GLOSSARY

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Title Description
Decagon A 10-sided polygon is called a decagon.
Deductive Logic Deductive Logic is employed before events have transpired, before the fact.
Degree, Angle One 360th of a full rotation is an angle of one degree.
Diagonal Convex polygons have Diagonals from each vertex to each non-adjoining vertex.
Dilation To grow in size is to dilate, or to undergo Dilation.
Most often it means to increase proportionally in all dimensions, but not strictly.
Sometimes Dilation is expansion in one dimension only.
Dimension A line has one Dimension.
A plane has two Dimensions.
A three-dimensional object occupies space.
Directrix A line specific to conic sections hyperbolas, parabolas, and ellipses, known as a Directrix, serves to describe along with the location of the focus (or foci) the loci (points) on the graph of the function.
Disk A Disk is most often a circular object with a relatively thin measure in the direction orthogonal to the plane of the circular bases.
Distance A length from one point to another is considered a Distance.
Any measurement in one dimension confers a length, which is Distance.
Dodecagon A 12-sided polygon is a Decagon.
Dodecahedron A 12-faced polyhedron is called a Dodecahedron.

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