Circle theorem

Circle theorem may refer to:

• Any of many theorems related to the circle; often taught as a group in GCSE mathematics. These include:
  • Inscribed angle theorem.
  • Thales' theorem, if A, B and C are points on a circle where the line AC is a diameter of the circle, then the angle ∠ABC is a right angle.
  • Alternate segment theorem.
  • Ptolemy's theorem.
• The Milne-Thomson circle theorem in fluid dynamics.
• Five circles theorem
• Six circles theorem
• Seven circles theorem
• Gershgorin circle theorem

• Clifford's circle theorems
• Descartes' theorem also known as 'kissing circles' or 'Soddy circles' theorem
• List of circle topics