Category:三角形と円に関する定理

Six circles theorem

Musselman's theorem

Fuhrmann circle

Cramer–Castillon problem

Van Lamoen circle

Simson line

Harcourt's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Miquel's theorem

Kosnita's theorem

Pompeiu's theorem

Reuschle's theorem

Lester's theorem

Japanese theorem for cyclic polygons

Griffiths' theorem

Conway circle theorem

Incenter–excenter lemma

Thébault's theorem

Van Schooten's theorem

Lune of Hippocrates

Thales's theorem