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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.


Not lying on the same line.


Lying on the same line.


a flat surface with infinite length and width but no thickness.


Lying in the same plane.


part of a line that begins from an endpoint and extends infitnitely in one direction.


a mathematical statement assumed to be true.


a mathematical statement that has been or is to be proved on the basis of established definitions and properties.


a clear, logical structure of reasoning that begins from accepted ideas and proceeds through logic to reach a conclusion.


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.


the point at which the perpendicular bisectors of each side of the triangle meet.


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.


the point of intersection of the three medians of the triangle.

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