![Notes on a triangle](/sites/default/files/styles/medium/public/thumbnails/content-id-5920-icon.jpg?itok=lB78dQH3)
Symmetry
![Notes on a triangle](/sites/default/files/styles/medium/public/thumbnails/content-id-5920-icon.jpg?itok=lB78dQH3)
![Coordinate Challenge](/sites/default/files/styles/medium/public/thumbnails/content-id-5038-icon.jpg?itok=KAFdXOKr)
problem
Coordinate Challenge
Use the clues about the symmetrical properties of these letters to place them on the grid.
![Rotations Are Not Single Round Here](/sites/default/files/styles/medium/public/thumbnails/content-id-4914-icon.jpg?itok=pNxbUciY)
problem
Rotations Are Not Single Round Here
I noticed this about streamers that have rotation symmetry : if
there was one centre of rotation there always seems to be a second
centre that also worked. Can you find a design that has only one
centre of rotation ? Or if you thought that was impossible, could
you say why ?
![One Reflection Implies Another](/sites/default/files/styles/medium/public/thumbnails/content-id-4913-icon.jpg?itok=nSsXLApM)
problem
One Reflection Implies Another
When a strip has vertical symmetry there always seems to be a
second place where a mirror line could go. Perhaps you can find a
design that has only one mirror line across it. Or, if you thought
that was impossible, could you explain why ?
![A Roll Of Patterned Paper](/sites/default/files/styles/medium/public/thumbnails/content-id-4912-icon.jpg?itok=G4m0HT5F)
problem
A Roll Of Patterned Paper
A design is repeated endlessly along a line - rather like a stream
of paper coming off a roll. Make a strip that matches itself after
rotation, or after reflection
![Symmetric Trace](/sites/default/files/styles/medium/public/thumbnails/content-id-4868-icon.png?itok=cuLTHDyY)
problem
Symmetric Trace
Points off a rolling wheel make traces. What makes those traces
have symmetry?
![Stringy Quads](/sites/default/files/styles/medium/public/thumbnails/content-id-2913-icon.png?itok=Qui2Dqz_)
problem
Stringy Quads
This practical problem challenges you to make quadrilaterals with a loop of string. You'll need some friends to help!
![Angular Reflection](/sites/default/files/styles/medium/public/thumbnails/content-id-2836-icon.png?itok=A2E6V5Y2)
problem
Angular Reflection
Weekly Problem 28 - 2013
Two lines meet at a point. Another line through this point is reflected in both of these lines. What is the angle between the image lines?
Two lines meet at a point. Another line through this point is reflected in both of these lines. What is the angle between the image lines?
![Octa-flower](/sites/default/files/styles/medium/public/thumbnails/content-id-2689-icon.png?itok=6mzpGCMz)
problem
Octa-flower
Join some regular octahedra, face touching face and one vertex of
each meeting at a point. How many octahedra can you fit around this
point?
![Pitchfork](/sites/default/files/styles/medium/public/thumbnails/content-id-2678-icon.png?itok=ntsUezkj)