New posts in Plane Geometry

Geometry problem involving a cyclic quadrilateral and power of a point theorem?

How to construct an equilateral triangle on 2 concentric circles

If $AB\parallel DC$, $BC\parallel AD$, and $AC\parallel DQ$, find $\Bbb X$ in terms of the areas $\Bbb A$, $\Bbb B$, and $\Bbb C$.

Convex cyclic hexagon $ABCDEF$. Prove $AC \cdot BD \cdot CE \cdot DF \cdot AE \cdot BF \geq 27 AB \cdot BC \cdot CD \cdot DE \cdot EF \cdot FA$

How to find a point on a line that minimizes sum of distances from three given points?

Packing of parallelograms with sides $1$ and $\sqrt{2}$ and angle $45^{\circ}$ in a rectangular container

Simson line in the regular 17-gon

Why are parallelograms defined as quadrilaterals? What term would encompass polygons with greater than two parallel pairs?

Geometry problem (proving a relation between sides of a triangle)

Does there exist a partition of an L to create a square?