Triangles

  • Property chart
    problem

    Property chart

    Age
    11 to 14
    Challenge level
    filled star filled star empty star

    A game in which players take it in turns to try to draw quadrilaterals (or triangles) with particular properties. Is it possible to fill the game grid?

  • Shapely pairs
    problem

    Shapely pairs

    Age
    11 to 14
    Challenge level
    filled star filled star empty star

    A game in which players take it in turns to turn up two cards. If they can draw a triangle which satisfies both properties they win the pair of cards. And a few challenging questions to follow...

  • Board Block
    problem

    Board block

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

    Take it in turns to make a triangle on the pegboard. Can you block your opponent?

  • Nine-Pin Triangles
    problem

    Nine-pin triangles

    Age
    7 to 11
    Challenge level
    filled star empty star empty star

    How many different triangles can you make on a circular pegboard that has nine pegs?

  • Triangle Pin-Down
    problem

    Triangle pin-down

    Age
    7 to 11
    Challenge level
    filled star filled star filled star
    Use the interactivity to investigate what kinds of triangles can be drawn on peg boards with different numbers of pegs.
  • Triangles all Around
    problem

    Triangles all around

    Age
    7 to 11
    Challenge level
    filled star filled star filled star

    Can you find all the different triangles on these peg boards, and find their angles?

  • Stellar Angles
    problem

    Stellar angles

    Age
    11 to 14
    Challenge level
    filled star empty star empty star
    Weekly Problem 30 - 2013
    What is the angle $x$ in the star shape shown?
  • Equal Lengths
    problem

    Equal lengths

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Weekly Problem 29 - 2013
    An equilateral triangle is drawn inside a rhombus, both with equal side lengths. What is one of the angles of the rhombus?
  • Parallelogram in the Middle
    problem

    Parallelogram in the middle

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Weekly Problem 27 - 2013
    The diagram shows a parallelogram inside a triangle. What is the value of $x$?
  • Isosceles Triangles
    problem

    Isosceles triangles

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Draw some isosceles triangles with an area of $9$cm$^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?