Book:Euclid/The Elements/Book IV

Contents

 * Book IV: Circles: Inscription and Circumscription
 * Definitions
 * Proposition 1: Fitting Chord Into Circle
 * Proposition 2: Inscribing in Circle Triangle Equiangular with Given
 * Proposition 3: Circumscribing about Circle Triangle Equiangular with Given
 * Proposition 4: Inscribing Circle in Triangle
 * Proposition 5: Circumscribing Circle about Triangle
 * Proposition 6: Inscribing Square in Circle
 * Proposition 7: Circumscribing Square about Circle
 * Proposition 8: Inscribing Circle in Square‎
 * Proposition 9: Circumscribing Circle about Square
 * Proposition 10: Construction of Isosceles Triangle whose Base Angle is Twice Apex
 * Proposition 11: Inscribing Regular Pentagon in Circle
 * Proposition 12: Circumscribing Regular Pentagon about Circle
 * Proposition 13: Inscribing Circle in Regular Pentagon
 * Proposition 14: Circumscribing Circle about Regular Pentagon
 * Proposition 15: Inscribing Regular Hexagon in Circle
 * Proposition 16: Inscribing Regular 15-gon in Circle