Term
concave (nonconvex) polygon 

Definition
A polygon in which at least one vertex is "pushed in." 


Term

Definition
A polygon in which all vertices are "pushed outward." 


Term

Definition
A point at the end of a line segment or ray. 


Term

Definition
Informally, a straight path that extends infinitely in opposite directions. 


Term

Definition
A straight path joining two points. 


Term

Definition
A quadrilateral that has two pairs of parallel sides. Opposite sides are equal length. Opposite angles have the same measure. 


Term

Definition
A 2dimensional figure that is made up of three or more line segments joined end to end to make one closed path. The line segments may not cross. 


Term
quadrangle (quadrilateral) 

Definition
A polygon that has four sides and four angles. 


Term

Definition
A straight path that extends infinitely from its endpoint. 


Term

Definition
A quadrilateral whose sides are all the same length and opposite sides are parallel. 


Term

Definition
A quadrilateral that has exactly one pair of parallel sides. 


Term

Definition
The point where the rays of an angle, the sides of a polygon, or the edges of a polyhedron meet. 

