15 terms

# Geometry Unit 1 Vocab

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Line Segments
a part of a line; it includes any two points on the line and all the points in between those two points.
Noncollinear
Not lying on the same line.
Collinear
Lying on the same line.
Plane
a flat surface with infinite length and width but no thickness.
Coplanar
Lying in the same plane.
Ray
part of a line that begins from an endpoint and extends infitnitely in one direction.
Postulate
a mathematical statement assumed to be true.
Theorem
a mathematical statement that has been or is to be proved on the basis of established definitions and properties.
Proof
a clear, logical structure of reasoning that begins from accepted ideas and proceeds through logic to reach a conclusion.
Incenter
the center of the circle that can be inscribed within a figure.
Inscribed Circle
a circle inside a figure and touching exactly one point on each side of the figure.
Circumcenter
the point at which the perpendicular bisectors of each side of the triangle meet.
Circumscribed
encircling and touching each vortex of another figure; a circle is circumscribed about a triangle if each vortex of the triangle lies on the circle.
Median of a Triangle
a straight line that goes through both the vortex and the midpoint of the opposite side, and it divides the triangle into two equal areas.
Centroid
the point of intersection of the three medians of the triangle.