points that lie on the same line
points that do not lie on the same line
a mathematical statement that can be proved
an unproved assumption
two collinear rays that have a common endpoint and extend in different directions
a pair of angles such that the rays forming the sides of one and the rays forming the sides of the other are opposite rays
a perpendicular segment from a vertex of a triangle to the opposite side
a line introduced into a diagram for the purpose of clarifying a proof
a polygon in which each interior angle has a measure less than 180
lying in the same plane
the length of the shortest path between two objects
the first and fourth terms of a proportion
the point of intersection of a line and a plane
the second and third terms of a proportion
the point of concurrency of the altitudes of a triangle
the point of concurrency of the perpendicular bisectors of the triangle's sides
the point of concurrency of the medians of a triangle
an equation stating that two or more ratios are equal
a quotient of two numbers
a polygon that is both equilateral and equiangular
two lines that are not coplanar
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