Prove that the polygon of $n$ sides with the biggest area, inscribed in a circumference, is always a regular polygon
101339
Area of a cyclic polygon maximum when it is a regular polygon
32009
Prove $\;\big((p\rightarrow q) \lor (p \rightarrow r)\big) \rightarrow (q\lor r)\equiv p \lor q \lor r$ without use of a truth table.
88283
Proving the length of angle bisector
78804
Proving that $\mathscr L=\{0^n \big|\text{n is the square of a natural number }\}$ is non regular using the pumping lemma
55491
Find the area of largest rectangle that can be inscribed in an ellipse
44070
Recurrence  for number of regions formed by diagonals of a convex polygon.
115677
Prove the equality of circle's areas
134081
What is the Cartesian product of $n$ polygons?
46309
Prove that this graph is nonplanar
84813
Rectangle inscribed in a right triangle with largest perimeter
134652
Prove that the perpendicular bisectors of the sides of a triangle meet at a point
62755
The simplest way of proving that $|\mathcal{P}(\mathbb{N})| = |\mathbb{R}| = c$
103416
Proving area under curve
111903
An inequality for sides of a triangle
32772
Proving units in a ring
10515
Area of an irregular polygon
62126
Constructing a triangle given 2 sides and the inscribed circle's radius