How to prove that a hexagon is the regular polygon with the most sides that can tile a plane
71711
Why a tesselation of the plane by a convex polygon of 7 or more sides is not possible?
90056
A synthetic geometrical proof required on a result regarding Isosceles triangles.
101339
Area of a cyclic polygon maximum when it is a regular polygon
84122
Convex Quadrilateral Test
106327
Prove, in this figure, that $EFGH$ is a parallelogram
37984
Prove a planar graph with all regions having even degree can be colored with 2 colors
16582
Show that $n$ lines separate the plane into $\frac{n^2+n+2}{2}$ regions
83788
Condition on sides of triangle to proof it is isoceles
140625
What is the area of a polygon with n equal length sides?
148307
Intersection of Altitudes in Hexagon
156302
Find conditions for a surface of rotation to be regular
86595
Draw Vertices of Regular Polygon
73832
How to find the maximum diagonal length inside a dodecahedron?
52316
Geodesics and Curves on a Plane
27454
Calculate the area of an irregular cyclic convex polygon
130851
Squaring the plane, with consecutive integer squares. And a related arrangement
19601
How can I make a material only apply to a side of a plane?