Circle Theorems Overview:

Chord of a Circle Theorem:

Fraction Study:

Thales’ Theorem, Proof:

Thales’ theorem: if AC is a diameter and B is a point on the diameter's circle, the angle ∠ ABC is a right angle.

Thales’ Theorem, Applied:

Wilder w/ Ellipse Construction:

Cyclic Quadrilateral, Proof:

Five Circle Theorem:

Same Arc Theorem:

Angles at Center Theorem:

Tangent Proof by Contradiction:

Ellipse Construction:

Angles in a Circle Theorem: