Subsection: Definitions from Book 4

This subsection lists the definitions from Book 4 of "Euclid’s Elements". Euclid’s definitions avoid figures. At BookOfProofs, figures are given for the most definitions.

  1. Definition: 4.1: Rectilinear Figure Inscribed in Another Rectilinear Figure
  2. Definition: 4.2: Rectilinear Figure Circumscribed about Another Rectilinear Figure
  3. Definition: 4.3: Inscribing Rectilinear Figures in Circles
  4. Definition: 4.4: Circumscribing Rectilinear Figures about Circles
  5. Definition: 4.7: Chord and Secant
  6. Definition: 4.6: Circumscribing Circles about Rectilinear Figures
  7. Definition: 4.5: Inscribing Circles in Rectilinear Figures

Thank you to the contributors under CC BY-SA 4.0!



Adapted from CC BY-SA 3.0 Sources:

  1. Callahan, Daniel: "Euclid’s 'Elements' Redux" 2014
  2. Prime.mover and others: "Pr∞fWiki",, 2016


  1. Health L. Thomas (Transl.): "Euclid's Elements - all thirteen books", Green Lion Press, 2013,