Linked from

The 13 pages that link to Thales' theorem, each with the reason it gives.

• Right triangleRelated: A diameter and a point on its circle construct a right triangle.

• CircumcircleRelated: A triangle inscribed in a semicircle is right-angled, making its hypotenuse a diameter.

• Inscribed angle theoremRelated: It is the inscribed angle theorem applied to a 180-degree central angle.

• Similar trianglesRelated: Parallel lines create smaller triangles with equal angles and proportional sides.

• DiameterRelated: A diameter forms the side opposite the right angle in every such inscribed triangle.

• Similarity (geometry)Related: Parallel lines create smaller triangles similar to the original, enabling length calculations.

• Right angleRelated: A diameter and a point on its circle construct a right angle.

• Similarity transformationRelated: It uses similarity to infer inaccessible lengths from proportional segments.

• Angle bisector theoremRelated: Parallel-line proportionality supports a standard proof of the angle bisector theorem.

• Midpoint theoremRelated: A parallel-line proportion gives a direct route to the midpoint relationship.