Proof without words!!

interesting!!

*area of a circle:

*src:
http://youtube.com/watch?v=whYqhpc6S6g




* numbers/number theory:

http://nrich.maths.org/5403

http://brownsharpie.courtneygibbons.org/?p=11

http://www.numbertheory.org/ntw/N3.html

http://math-frolic.blogspot.in/