Show the cirucumcircles of all triangles $PAB$ have the same radius
56320
Prove that the circumradius of $\triangle PAB$ is constant
39007
Identical balls arrangement in a circle
72707
Property of Medians and Cirumcircle
154864
Finding the radius of a third tangent circle
61344
How to relate areas of circle, square, rectangle and triangle if they have same perimeter??
148147
Three circles having centres on the three sides of a triangle
145214
Showing the power set is equinumerous to ${}^X2$
155241
How do we know the ratio between circumference and diameter is the same for all circles?
94051
How to show that all points are inside of unit circle?
66239
Verifying that a certain collection of intervals of $\mathbb R$ forms a topology
2575
Showing that $\mathbb{R}$ is connected
130436
bisectors of an angle in a triangle intersect at a single point - proof verification
57406
Proving the volume of a cone
94363
Prove: Any open interval has the same cardinality of $\Bbb R$ (without using trigonometric functions)
89493
Prove that circumcentre of $ABH,BCH,CAH$ are the vertices of a triangle congruent to $ABC$
149104
Coloring $\mathbb R^n$ with $n$ colors always gives us a color with all distances.
18380
Proof that Pi is constant (the same for all circles), without using limits