Category:三角形と円に関する定理

Musselman's theorem

Cramer–Castillon problem

Japanese theorem for cyclic polygons

Simson line

Harcourt's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Griffiths' theorem

Van Lamoen circle

Fuhrmann circle

Kosnita's theorem

Lester's theorem

Lune of Hippocrates

Reuschle's theorem

Pompeiu's theorem

Van Schooten's theorem

Six circles theorem

Conway circle theorem

Thébault's theorem

Miquel's theorem

Incenter–excenter lemma

Thales's theorem