Category:三角形と円に関する定理

Musselman's theorem

Van Schooten's theorem

Simson line

Cramer–Castillon problem

Incenter–excenter lemma

Pompeiu's theorem

Van Lamoen circle

Lune of Hippocrates

Thales's theorem

Six circles theorem

Thébault's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Reuschle's theorem

Fuhrmann circle

Kosnita's theorem

Feuerbach's theorem

Harcourt's theorem

Lester's theorem

Lexell's theorem

Griffiths' theorem

Conway circle theorem

Miquel's theorem

Japanese theorem for cyclic polygons