Skip to main content
Home
plus.maths.org

Secondary menu

  • My list
  • About Plus
  • Sponsors
  • Subscribe
  • Contact Us
  • Log in
  • Main navigation

  • Home
  • Articles
  • Collections
  • Podcasts
  • Maths in a minute
  • Puzzles
  • Videos
  • Topics and tags
  • For

    • cat icon
      Curiosity
    • newspaper icon
      Media
    • graduation icon
      Education
    • briefcase icon
      Policy

    Popular topics and tags

    Shapes

    • Geometry
    • Vectors and matrices
    • Topology
    • Networks and graph theory
    • Fractals

    Numbers

    • Number theory
    • Arithmetic
    • Prime numbers
    • Fermat's last theorem
    • Cryptography

    Computing and information

    • Quantum computing
    • Complexity
    • Information theory
    • Artificial intelligence and machine learning
    • Algorithm

    Data and probability

    • Statistics
    • Probability and uncertainty
    • Randomness

    Abstract structures

    • Symmetry
    • Algebra and group theory
    • Vectors and matrices

    Physics

    • Fluid dynamics
    • Quantum physics
    • General relativity, gravity and black holes
    • Entropy and thermodynamics
    • String theory and quantum gravity

    Arts, humanities and sport

    • History and philosophy of mathematics
    • Art and Music
    • Language
    • Sport

    Logic, proof and strategy

    • Logic
    • Proof
    • Game theory

    Calculus and analysis

    • Differential equations
    • Calculus

    Towards applications

    • Mathematical modelling
    • Dynamical systems and Chaos

    Applications

    • Medicine and health
    • Epidemiology
    • Biology
    • Economics and finance
    • Engineering and architecture
    • Weather forecasting
    • Climate change

    Understanding of mathematics

    • Public understanding of mathematics
    • Education

    Get your maths quickly

    • Maths in a minute

    Main menu

  • Home
  • Articles
  • Collections
  • Podcasts
  • Maths in a minute
  • Puzzles
  • Videos
  • Topics and tags
  • Audiences

    • cat icon
      Curiosity
    • newspaper icon
      Media
    • graduation icon
      Education
    • briefcase icon
      Policy

    Secondary menu

  • My list
  • About Plus
  • Sponsors
  • Subscribe
  • Contact Us
  • Log in
  • Dodecahedron

    Mathematical Misfits

    1 May, 2002
    May 2002

    Two-dimensional

    Which fits best - a square peg in a round hole, or a round peg in a square hole? To be more precise, if you take a circle and fit inside it the largest possible square, and then take a square and fit inside it the largest possible circle, which leaves proportionally least space?

     

    Which fits best?

    Which fits best?

     

    Three-dimensional

    Which fits best in a sphere - a dodecahedron or an icosahedron? That is, if you fit the largest possible dodecahedron and icosahedron inside a given sphere, which leaves least space?

     

    Dodecahedron

    Dodecahedron

    Icosahedron

    Icosahedron

    You can see rotating versions of these here (70k download each).

    (Both images copyright by Rüdiger Appel)


    You can send your solution by e-mail to plus@maths.cam.ac.uk.

    If you are stumped by last issue's puzzle, here is the solution.

    For some challenging mathematical puzzles, see the NRICH puzzles from this month or last month.

    Solution link
    Mathematical misfits two-dimensional solution
    • Log in or register to post comments
    University of Cambridge logo

    Plus is part of the family of activities in the Millennium Mathematics Project.
    Copyright © 1997 - 2025. University of Cambridge. All rights reserved.

    Terms