Ratio and proportion

There are 112 NRICH Mathematical resources connected to Ratio and proportion
Once Upon a Time
problem

Once upon a time

Age
7 to 11
Challenge level
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Can you work out the height of Baby Bear's chair and whose bed is whose if all the things the three bears have are in the same proportions?
Rarity
problem

Rarity

Age
16 to 18
Challenge level
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Show that it is rare for a ratio of ratios to be rational.
Mixed up mixture
problem

Mixed up mixture

Age
14 to 16
Challenge level
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Can you fill in the mixed up numbers in this dilution calculation?

Halving the Triangle
problem

Halving the triangle

Age
16 to 18
Challenge level
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Draw any triangle PQR. Find points A, B and C, one on each side of the triangle, such that the area of triangle ABC is a given fraction of the area of triangle PQR.
Points in Pairs
problem

Points in pairs

Age
14 to 16
Challenge level
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Move the point P to see how P' moves. Then use your insights to calculate a missing length.
Dilution series calculator
problem

Dilution series calculator

Age
14 to 16
Challenge level
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Which dilutions can you make using 10ml pipettes and 100ml measuring cylinders?

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?
A Shade Crossed
problem

A shade crossed

Age
14 to 16
Challenge level
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Find the area of the shaded region created by the two overlapping triangles in terms of a and b?
Scale Draw
problem

Scale draw

Age
5 to 7
Challenge level
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Use the grids to draw pictures to different scales.
Six Notes all Nice Ratios
problem

Six notes all nice ratios

Age
14 to 16
Challenge level
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The Pythagoreans noticed that nice simple ratios of string length made nice sounds together.