Constructions

  • Kissing
    problem

    Kissing

    Age
    16 to 18
    Challenge level
    filled star filled star empty star
    Two perpendicular lines are tangential to two identical circles that touch. What is the largest circle that can be placed in between the two lines and the two circles and how would you construct it?
  • Pareq Exists
    problem

    Pareq Exists

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    Prove that, given any three parallel lines, an equilateral triangle always exists with one vertex on each of the three lines.
  • The medieval octagon
    problem

    The Medieval Octagon

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    Medieval stonemasons used a method to construct octagons using ruler and compasses... Is the octagon regular? Proof please.
  • Pentabuild
    problem

    Pentabuild

    Age
    16 to 18
    Challenge level
    filled star filled star empty star
    Explain how to construct a regular pentagon accurately using a straight edge and compass.
  • Circle Scaling
    problem

    Circle Scaling

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    Describe how to construct three circles which have areas in the ratio 1:2:3.
  • Two Points Plus One Line
    problem

    Two Points Plus One Line

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    Draw a line (considered endless in both directions), put a point somewhere on each side of the line. Label these points A and B. Use a geometric construction to locate a point, P, on the line, which is equidistant from A and B.
  • Half a Triangle
    problem

    Half a Triangle

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.
  • A Patchwork Piece
    problem

    A Patchwork Piece

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    Follow the diagrams to make this patchwork piece, based on an octagon in a square.
  • Yin Yang
    problem

    Yin Yang

    Age
    7 to 11
    Challenge level
    filled star filled star filled star
    Can you reproduce the Yin Yang symbol using a pair of compasses?
  • LOGO Challenge 2 - Diamonds are forever
    problem

    Logo Challenge 2 - Diamonds Are Forever

    Age
    7 to 16
    Challenge level
    filled star empty star empty star

    The challenge is to produce elegant solutions. Elegance here implies simplicity. The focus is on rhombi, in particular those formed by jointing two equilateral triangles along an edge.