Table of Contents

1. Circle Vocabulary
   1. Circle Terminology
   2. Circle Tangent-Types Illustrator
   3. Similar Circles?
   4. Congruent Circles: Definition
2. Tangents
   1. Properties of Tangents Drawn to Circles (A)
   2. Properties of Tangents Drawn to Circles (B)
   3. Properties of Tangents
   4. Tangents to Circles: Investigation
   5. Int+Ext Tangent Action!
   6. GoGeometry Action 6!
3. Inscribed Angle Theorems & Corollaries
   1. Inscribed Angle Theorem (V1)
   2. Inscribed Angle Theorem: Take 2!
   3. Inscribed Angle Theorems: Take 3!
   4. Proof Exercise: Inscribed Angle Theorem (Case 1)
   5. Proof Exercise: Inscribed Angle Theorem (Case 2)
   6. Proof Exercise: Inscribed Angle Theorem (Case 3)
   7. Where to Sit? (I)
   8. Where to Sit (II)?
   9. Inscribed Angle Theorem: Corollary 1
   10. Inscribed Angle Theorem Dance: Take 2!
   11. Animation 20 (Inscribed Angle Dance!)
   12. Thales' Theorem (VA)
   13. Thales' Theorem (VB)
   14. Inscribed Angle Intercepts Semicircle
   15. Cyclic Quadrilaterals (IAT: Corollary 3)
   16. Inscribed Angle Theorems: Take 4!
   17. Geometric Mean Illustration
4. Theorems Involving Chords
   1. Congruent Chords: Quick Investigation
   2. Congruent Chords (I)
   3. Diameters & Chords I (VA)
   4. Diameters & Chords I (VB)
   5. Angle Formed by 2 Chords (I)
   6. Angle Formed by 2 Chords (II)
   7. Angle Formed by Chord & Tangent (I)
   8. Angle Formed by Chord & Tangent (II)
   9. Crossing Chords: Proof Hint
   10. Congruent Chords Action (A)
   11. Equidistant Chord Action
   12. Butterfly Theorem Action!
   13. Cut-The-Knot Action (2) !!!
   14. GoGeometry Action 1!
   15. GoGeometry Action 2!
   16. GoGeometry Action 3!
   17. GoGeometry Action 5!
   18. GoGeometry Action 8!
   19. Cut-The-Knot Action (6)!
   20. GoGeometry Action 9!
   21. GoGeometry Action 15!
   22. Cut-The-Knot Action 7!
   23. GoGeometry Action 19!
5. Secant & Tangent Theorems
   1. Angles from Secants and Tangents (V1)
   2. Angle From 2 Secants (V2)
   3. Secants: Proof Hint
   4. Not Your Everyday Chord & Tangent Theorem
   5. GoGeometry Action 4!
   6. GoGeometry Action 13!
   7. GoGeometry Action 16!
   8. Thales Action + Sequel = GoGeometry Action 25!
   9. GoGeometry Action 26!
6. Older (Earlier) Applets
   1. Inscribed Angle Theorem (Proof without Words)
   2. Inscribed Angle Theorem (Corollary 1) (Proof without Words)
   3. Inscribed Angle Theorem (Corollary 2) (Proof without Words)
   4. Inscribed Angle Theorem (Corollary 3) Cyclic Quadrilaterals
   5. Angle formed by a Secant & Tangent: What Do You See? (V1)
   6. Angle Formed by a Secant & Tangent: What Do You See? (V2)
   7. Angle Formed by 2 Tangents (V2): What Do You See?
   8. Cyclic Quadrilaterals
   9. Congruent Chords in the Same Circle
   10. Inscribed Angle Theorem (Intro): What Do You See Here?
   11. Inscribed Angle Action !!!
   12. Inscribed Angle Action! (2 Theorems)
   13. Angle Formed by 2 Chords (V1): What Do You See?
   14. Angle Formed by 2 Chords (V2): What Do You See?
   15. Chords Equidistant from Circle's Center
   16. Crossing Chords Property & Proof Start
   17. Crossing Chords Property & Proof Start (II)