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A game you're almost certain to lose...

What are the challenges of communicating from the frontiers of mathematical research, and why should we be doing it?

Maths meets politics as early career mathematicians present their work at the Houses of Parliament.

Celebrate this year's International Women's Day with some of the articles and podcasts we have produced with women mathematicians over the last year!

How to sum an infinite series using chocolate.

The link

http://www.cut-the-knot.org/triangle/pythpar/PTimpliesPP.shtml

shows how the Pythagorean Theorem is equivalent to the Parallel Postulate. In my mind the parallel postulate was always linked to ideas of similarity, scaling and multiplication ( constructing similar triangles is effectively multiplying one line segment by another ). Does the equivalence to the Pythagorean theorem mean that the fifth dictates how area is to be defined in an Euclidean Geometry? Or that how area is defined determines the geometry?