Similarity and congruence

  • Chord
    problem

    Chord

    Age
    16 to 18
    Challenge level
    filled star empty star empty star
    Equal touching circles have centres on a line. From a point of this line on a circle, a tangent is drawn to the farthest circle. Find the lengths of chords where the line cuts the other circles.
  • Another Triangle in a Triangle
    problem

    Another triangle in a triangle

    Age
    16 to 18
    Challenge level
    filled star filled star empty star

    Can you work out the fraction of the original triangle that is covered by the green triangle?