New posts in triangles

Ellipse in the triangle

triangles analytic-geometry conic-sections tangent-line

Pythagorean theorem expressed without roots in an old Tamilian (Indian) statement

triangles approximation math-history pythagorean-triples

Sum of angles under which a fixed line segment is seen from points situated on another line segment

calculus geometry algebra-precalculus trigonometry triangles

How to find triangle vertices given midpoints?

geometry triangles

Find area of the triangle ABC, given the coordinates of vertices in plane

geometry analytic-geometry triangles area

uniqueness of barycentric coordinates of a simplex

linear-algebra triangles simplex barycentric-coordinates

Joint PDF of two random variables in a triangle

probability random-variables triangles

How to calculate the side of a right triangle from the coordinates of points and the length of one side?

geometry triangles pythagorean-triples

Find how many parts are in a triangle

geometry triangles

How to prove $\Delta DEF$ is an equilateral triangle?

geometry triangles

What is a geometric construction corresponding to elliptic curve addition for Sharygin-isosceles triangles?

euclidean-geometry triangles elliptic-curves plane-geometry

Does the function $x \mapsto \sqrt{1-x^2}$ have a name?

calculus geometry terminology triangles education

A curious property of an acute triangle

geometry triangles

How does this equation to find the radius from 3 points actually work?

geometry circles triangles

Equilateral triangle inscribed in a triangle

geometry triangles

Concentric Equilateral Triangles

geometry dynamical-systems euclidean-geometry triangles solid-geometry

Torricelli points on a circle

geometry triangles circles plane-geometry

Given $\triangle ABC$ with $\angle C = 60^\circ$, show $a^2+b^2-ab=c^2$ without trigonometry

geometry euclidean-geometry triangles

Question about the encyclopedia of triangle centers

geometry euclidean-geometry triangles

$ABCD$ is a square. $M$ and $N$ are points on $AB $ and $BC$, respectively such that $\angle MDN=45^\circ$...

geometry triangles