Project Gutenberg`s The Foundations of Geometry, by David Hilbert
... A, B, C, D, . . . , K the vertices. Polygons having 3, 4, 5, . . . , n vertices are called, respectively, triangles, quadrangles, pentagons, . . . , n-gons. If the vertices of a polygon are all distinct and none of them lie within the segments composing the sides of the polygon, and, furthermore, if ...
... A, B, C, D, . . . , K the vertices. Polygons having 3, 4, 5, . . . , n vertices are called, respectively, triangles, quadrangles, pentagons, . . . , n-gons. If the vertices of a polygon are all distinct and none of them lie within the segments composing the sides of the polygon, and, furthermore, if ...
Is it As Parallelogram?
... The single arcs make the top and bottom parallel. The double arcs make the left and right parallel. Both of these are by the Alternate Interior Angles Converse(2x). This figure is a parallelogram. Reason: Definition of parallelogram (Both pair of opposite sides are parallel.) ...
... The single arcs make the top and bottom parallel. The double arcs make the left and right parallel. Both of these are by the Alternate Interior Angles Converse(2x). This figure is a parallelogram. Reason: Definition of parallelogram (Both pair of opposite sides are parallel.) ...