Ratio and proportion

There are 112 NRICH Mathematical resources connected to Ratio and proportion
How big?
problem

How big?

Age
11 to 14
Challenge level
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If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
One and three
problem

One and three

Age
14 to 16
Challenge level
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Two motorboats travelling up and down a lake at constant speeds leave opposite ends A and B at the same instant, passing each other, for the first time 600 metres from A, and on their return, 400 metres from B. How long is the lake?
Same Height
problem

Same Height

Age
14 to 16
Challenge level
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A trapezium is divided into four triangles by its diagonals. Can you work out the area of the trapezium?
Star Gazing
problem

Star Gazing

Age
14 to 16
Challenge level
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Find the ratio of the outer shaded area to the inner area for a six pointed star and an eight pointed star.
From all corners
problem

From all corners

Age
14 to 16
Challenge level
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Straight lines are drawn from each corner of a square to the mid points of the opposite sides. Express the area of the octagon that is formed at the centre as a fraction of the area of the square.
Square Pegs
problem

Square Pegs

Age
11 to 14
Challenge level
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Which is a better fit, a square peg in a round hole or a round peg in a square hole?
Rule of Three
problem

Rule of Three

Age
11 to 14
Challenge level
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If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Two Ladders
problem

Two Ladders

Age
14 to 16
Challenge level
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Two ladders are propped up against facing walls. The end of the first ladder is 10 metres above the foot of the first wall. The end of the second ladder is 5 metres above the foot of the second wall. At what height do the ladders cross?
Burning down
problem

Burning down

Age
14 to 16
Challenge level
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One night two candles were lit. Can you work out how long each candle was originally?
Gift of Gems
problem

Gift of Gems

Age
14 to 16
Challenge level
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Four jewellers share their stock. Can you work out the relative values of their gems?