Category:三角形と円に関する定理

Japanese theorem for cyclic polygons

Musselman's theorem

Miquel's theorem

Cramer–Castillon problem

Van Lamoen circle

Lune of Hippocrates

Incenter–excenter lemma

Van Schooten's theorem

Simson line

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Thébault's theorem

Fuhrmann circle

Kosnita's theorem

Pompeiu's theorem

Six circles theorem

Lester's theorem

Harcourt's theorem

Reuschle's theorem

Griffiths' theorem

Conway circle theorem

Lexell's theorem

Feuerbach's theorem

Thales's theorem