Maths · Rung 14 of 30

Proportions

If 3 cost 6, then 5 cost 6 × 5 / 3 = 10: the rule of three. On a 1:50,000 map, one centimetre is 50,000 cm, that is, 500 m. Speed is distance over time.

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Exercises from this rung

Generated by the app, from easiest to hardest

  1. At 90 km/h, how many km do you cover in 2 h?

    • 180 km
    • 92 km
    • 225 km
    • 45 km

    Why 90 km each hour, for 2 h: 90 × 2 = 180 km.

    easier

  2. At 60 km/h, how many km do you cover in 1 h?

    • 60 km
    • 120 km
    • 61 km
    • 90 km

    Why 60 km each hour, for 1 h: 60 × 1 = 60 km.

    in between

  3. On a 1:10,000 map, 6 cm is…

    • 600 m
    • 6,000 m
    • 60,000 m
    • 60 m

    Why 6 cm × 10,000 = 60,000 real cm; in metres, ÷ 100: 600 m.

    harder