Similarity and congruence

There are 62 NRICH Mathematical resources connected to Similarity and congruence
Sierpinski Triangle
problem

Sierpinski triangle

Age
16 to 18
Challenge level
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What is the total area of the triangles remaining in the nth stage of constructing a Sierpinski Triangle? Work out the dimension of this fractal.
Double Angle Triples
problem

Double angle triples

Age
16 to 18
Challenge level
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Try out this geometry problem involving trigonometry and number theory
Overlap
problem

Overlap

Age
14 to 16
Challenge level
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A red square and a blue square overlap. Is the area of the overlap always the same?

Squareflake
problem

Squareflake

Age
16 to 18
Challenge level
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A finite area inside and infinite skin! You can paint the interior of this fractal with a small tin of paint but you could never get enough paint to paint the edge.
Look before you leap
problem

Look before you leap

Age
14 to 16
Challenge level
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Can you spot a cunning way to work out the missing length?
Chord
problem

Chord

Age
16 to 18
Challenge level
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Equal touching circles have centres on a line. From a point of this line on a circle, a tangent is drawn to the farthest circle. Find the lengths of chords where the line cuts the other circles.
Von Koch Curve
problem

Von koch curve

Age
16 to 18
Challenge level
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Make a poster using equilateral triangles with sides 27, 9, 3 and 1 units assembled as stage 3 of the Von Koch fractal. Investigate areas & lengths when you repeat a process infinitely often.
Pentakite
problem

Pentakite

Age
14 to 18
Challenge level
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Given a regular pentagon, can you find the distance between two non-adjacent vertices?
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?
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.