How good is Pythagoras’ theorem?

Welcome to Atharv’s Maths Blog! Today I will talk about Pythagoras’ theorem. If you don’t know, Pythagoras of Samos (550-495 BC) was a Greek thinker and the founder of the Pythagorean group. He formulated a theorem stating that \(a^2+b^2=c^2\) for only specific values of \(a\), \(b\) and \(c\). This theorem has over 200 proofs, but what we are most interested in for this post is how to generate those values of \(a\), \(b\) and \(c\). Let us take two integers \(m\) and \(n\) where \(m \ge 0\), \(n \ge 0\) and \(m \ge n\). Now the values of \(a\), \(b\) and \(c\) are given below. $$a = m^2 – n^2$$ $$b = 2mn$$ $$c = m^2+n^2$$ Very interesting… Is that because \(b + c = (m+n)^2\)?

Yes! \(b+c\) works out to \(m^2+n^2+2mn\), which, because of the famous algebraic identity, is \((m+n)^2\). So let us look at some examples. So if \(m=9\) and \(n=5\). Then the values of \(a\), \(b\) and \(c\) will be defined as follows: $$a=9^2 – 5^2=81-25=56$$ $$b=2\times9\times5=18\times5=90$$ $$c=9^2+5^2=81+25=106$$ So, as we can see, the triplets (Pythagoras’ triples or triplets are the values of \(a\), \(b\) and \(c\)) are 56, 90 and 106. And, the square of the first number plus the square of the second number is equal to the square of the third number! $$56^2+90^2=3136+8100=11236=106^2$$ Another example! If \(m=6\) and \(n=3\), then $$a=6^2-3^2=36-9=27$$ $$b=2\times6\times3=12\times3=36$$ $$c=6^2+3^2=36+9=45$$ The triplets in this case are 27, 36 and 45. And, 27 squared + 36 squared is indeed 45 squared! $$27^2+36^2=729+1296=2025=45^2$$ So now we know how to generate Pythagoras’ triplets. I hope I was able to make it interesting.

Right now, I am the only blogger on this blog, but I will add support for third-party bloggers, logins and signups.

This is the end of my first mathematical blog post. Have a nice day! See you next time!

By Atharv Nadkarni

Hello bloggers! I am Atharv Nadkarni. I am 8 years old and moving to the 3rd grade. I created this blog to share my interest in maths and science with you. There is also a guest blog section where you can share your interests in any subjects you want with me.

7 comments

  1. Very Well explained Atharv. Truly impressive.
    I wish you all the best for more & more blog writing in future.

  2. Wow !! That’s so well explained Atharva..
    That took me back to my school days

    Keep it up ..n come up with more informative work like this..

  3. Atharv as usual spectacular.Everytime you post matter on Mathematics it amazes me about your critical thinking and how well you put down concepts.Keep going.Sky is the limit.

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