Regular polygons and circles

  • Overlapping Circles
    problem

    Overlapping Circles

    Age
    7 to 11
    Challenge level
    1 out of 3

    What shaped overlaps can you make with two circles which are the same size?

  • Shedding Some Light
    problem

    Shedding Some Light

    Age
    7 to 11
    Challenge level
    1 out of 3
    Make an estimate of how many light fittings you can see. Was your estimate a good one? How can you decide?
  • Triangular Hexagons
    problem

    Triangular Hexagons

    Age
    7 to 11
    Challenge level
    1 out of 3
    Investigate these hexagons drawn from different sized equilateral triangles.
  • Like a Circle in a Spiral
    problem

    Like a Circle in a Spiral

    Age
    7 to 16
    Challenge level
    1 out of 3
    A cheap and simple toy with lots of mathematics. Can you interpret the images that are produced? Can you predict the pattern that will be produced using different wheels?
  • Lighting up time
    problem

    Lighting Up Time

    Age
    7 to 14
    Challenge level
    1 out of 3
    A very mathematical light - what can you see?
  • Kissing
    problem

    Kissing

    Age
    16 to 18
    Challenge level
    2 out of 3
    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?
  • Get Cross
    problem

    Get Cross

    Age
    14 to 16
    Challenge level
    2 out of 3
    A white cross is placed symmetrically in a red disc with the central square of side length sqrt 2 and the arms of the cross of length 1 unit. What is the area of the disc still showing?
  • Floored
    problem

    Floored

    Age
    14 to 16
    Challenge level
    2 out of 3
    A floor is covered by a tessellation of equilateral triangles, each having three equal arcs inside it. What proportion of the area of the tessellation is shaded?
  • Three four five
    problem

    Three Four Five

    Age
    14 to 16
    Challenge level
    2 out of 3
    Two semi-circles (each of radius 1/2) touch each other, and a semi-circle of radius 1 touches both of them. Find the radius of the circle which touches all three semi-circles.
  • Holly
    problem

    Holly

    Age
    14 to 16
    Challenge level
    2 out of 3
    The ten arcs forming the edges of the "holly leaf" are all arcs of circles of radius 1 cm. Find the length of the perimeter of the holly leaf and the area of its surface.