Similarity and congruence

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

Squareflake

Age
16 to 18
Challenge level
filled star filled star empty star
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.
Sierpinski Triangle
problem

Sierpinski Triangle

Age
16 to 18
Challenge level
filled star filled star empty star
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.
Guillotine
problem

Guillotine

Age
11 to 14
Challenge level
filled star filled star empty star
Weekly Problem 9 - 2006
What fraction of the area of the rectangle is shaded?
Triangle in a Triangle
problem

Triangle in a Triangle

Age
14 to 16
Challenge level
filled star filled star empty star
Can you work out the fraction of the original triangle that is covered by the inner triangle?
Figure of Eight
problem

Figure of Eight

Age
14 to 16
Challenge level
filled star filled star filled star
On a nine-point pegboard a band is stretched over 4 pegs in a "figure of 8" arrangement. How many different "figure of 8" arrangements can be made ?
Pentabuild
problem

Pentabuild

Age
16 to 18
Challenge level
filled star filled star empty star
Explain how to construct a regular pentagon accurately using a straight edge and compass.
Slippage
problem

Slippage

Age
14 to 16
Challenge level
filled star filled star empty star
A ladder 3m long rests against a wall with one end a short distance from its base. Between the wall and the base of a ladder is a garden storage box 1m tall and 1m high. What is the maximum distance up the wall which the ladder can reach?
Bus Stop
problem

Bus Stop

Age
14 to 16
Challenge level
filled star filled star filled star
Two buses leave at the same time from two towns Shipton and Veston on the same long road, travelling towards each other. At each mile along the road are milestones. The buses' speeds are constant and in the ratio 5 to 4. The buses travel to and fro between the towns. What milestones are at Shipton and Veston?
All Tied Up
problem

All Tied Up

Age
14 to 16
Challenge level
filled star filled star empty star
A ribbon runs around a box so that it makes a complete loop with two parallel pieces of ribbon on the top. How long will the ribbon be?
Squirty
problem

Squirty

Age
14 to 16
Challenge level
filled star filled star filled star
Using a ruler, pencil and compasses only, it is possible to construct a square inside any triangle so that all four vertices touch the sides of the triangle.