### Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

### Calendar Capers

Choose any three by three square of dates on a calendar page...

### Building Tetrahedra

Can you make a tetrahedron whose faces all have the same perimeter?

# Wood Pile Perimeter

##### Stage: 3 and 4 Short Challenge Level:

The diagram shows three touching circles each of radius $5$cm and a line which touches two of them.

Find, in terms of $\pi$, the total perimeter of the two shaded shapes.

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.
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