Ratio and proportion

  • Gassy information
    problem

    Gassy Information

    Age
    16 to 18
    Challenge level
    filled star filled star empty star
    Do each of these scenarios allow you fully to deduce the required facts about the reactants?
  • At a glance
    problem

    At a Glance

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?
  • Square Pegs
    problem

    Square Pegs

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Which is a better fit, a square peg in a round hole or a round peg in a square hole?
  • Same Height
    problem

    Same Height

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    A trapezium is divided into four triangles by its diagonals. Can you work out the area of the trapezium?
  • Around and Back
    problem

    Around and Back

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns around and heads back to the starting point where he meets the runner who is just finishing his first circuit. Find the ratio of their speeds.
  • Semi-Square
    problem

    Semi-Square

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    What is the ratio of the area of a square inscribed in a semicircle to the area of the square inscribed in the entire circle?
  • Rati-o
    problem

    Rati-O

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
  • Hello Again
    problem

    Hello Again

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Anne completes a circuit around a circular track in 40 seconds. Brenda runs in the opposite direction and meets Anne every 15 seconds. How long does it take Brenda to run around the track?
  • Bus Stop
    problem

    Bus Stop

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    Two buses leave at the same time from two towns Shipton and Veston on the same long road, travelling towards each other. At each mile along the road are milestones. The buses' speeds are constant and in the ratio 5 to 4. The buses travel to and fro between the towns. What milestones are at Shipton and Veston?
  • 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.