Category:三角形と円に関する定理

Thales's theorem

Musselman's theorem

Fuhrmann circle

Cramer–Castillon problem

Thébault's theorem

Van Lamoen circle

Harcourt's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Incenter–excenter lemma

Pompeiu's theorem

Lexell's theorem

Kosnita's theorem

Simson line

Six circles theorem

Miquel's theorem

Reuschle's theorem

Lester's theorem

Van Schooten's theorem

Griffiths' theorem

Conway circle theorem

Japanese theorem for cyclic polygons

Lune of Hippocrates