Ratio and proportion
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articlePi, a Very Special Number
Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible. -
articleRatio or Proportion?
An article for teachers which discusses the differences between ratio and proportion, and invites readers to contribute their own thoughts.
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problemPlane to See
P is the midpoint of an edge of a cube and Q divides another edge in the ratio 1 to 4. Find the ratio of the volumes of the two pieces of the cube cut by a plane through PQ and a vertex. -
problemFavouriteRule of Three
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall? -
problemRacing Odds
In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair? -
problemConical Bottle
A right circular cone is filled with liquid to a depth of half its vertical height. The cone is inverted. How high up the vertical height of the cone will the liquid rise? -
problemCircuit Training
Mike and Monisha meet at the race track, which is 400m round. Just to make a point, Mike runs anticlockwise whilst Monisha runs clockwise. Where will they meet on their way around and will they ever meet at the start again? If so, after how many circuits? -
problemTuning and Ratio
Why is the modern piano tuned using an equal tempered scale and what has this got to do with logarithms? -
problemSix Notes All Nice Ratios
The Pythagoreans noticed that nice simple ratios of string length made nice sounds together.