Category:三角形と円に関する定理

Feuerbach's theorem

Musselman's theorem

Simson line

Cramer–Castillon problem

Van Lamoen circle

Harcourt's theorem

Lune of Hippocrates

Incenter–excenter lemma

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Six circles theorem

Miquel's theorem

Thébault's theorem

Fuhrmann circle

Kosnita's theorem

Lester's theorem

Pompeiu's theorem

Reuschle's theorem

Japanese theorem for cyclic polygons

Van Schooten's theorem

Griffiths' theorem

Conway circle theorem

Thales's theorem

Lexell's theorem