Proof: any triangle can be dissected into more than six isosceles triangles
366
Can every triangle be divided into five isosceles triangles?
141482
Proof that plane with $N$ lines can be painted with two colors so that any two neighboring regions are painted in different colors
22237
Proof of triangle inequality
127866
Two triangles and their content ratio
112896
Construct the triangle with given angle bisectors
145181
How can I prove the maximum number of edges?
134454
Proof that every number ≥ $8$ can be represented by a sum of fives and threes.
128716
Intuitive/direct proof that a rectangle partitioned into rectangles each with at least one integer side must itself have an integer side
122998
number of edges induction proof
89501
Equidecomposability of a Cube into 6 Trirectangular Tetrahedra
11665
Show that $D_{12}$ is isomorphic to $D_6\times C_2$
35313
Proof of Euclid's Lemma
148147
Three circles having centres on the three sides of a triangle
36980
Prove the third isomorphism theorem
53499
Equilateral triangle inscribed in a triangle
145662
Prove that two lines are perpendicular in isosceles triangle geometrically
8469
Dividing an equilateral triangle into N equal (possibly non-connected) parts