## Wednesday, June 24, 2020

### Baudhayana: The man who knew Pythagoras theorem 300 years before him

Baudhayana is believed to have born around 800 BCE while Pythagoras was born in 570 BCE. The popular theorem that carries the name of Pythagoras says square of length of hypotenuse  is equal to sum of squares of two other sides in  a right angle triangle. While not said in so many words, here is what Boudhayana says in his book Sulba Sutra.

चतुरश्राच्चतुरश्रं निर्जिहीर्षन्यावन्निर्जिहीर्षेत्तस्य करण्या वर्षीयसो वृघ्रमुल्लिखेहृघ्रस्य
पार्श्वमानीमक्ष्णयेतरत्पार्श्वमुपसहंरेत्सा यत्र निपतेत्तदपच्छिन्धाच्छिन्नया निरस्तम्

If you wish to deduct one square from another use the following method.
1. Cut off from the larger one an oblong with the side of the smaller one
2. Draw one of the sides of that oblong across to the other side
3. Where it touches the other side, that piece cut off; but it the deduction is made
Look at the figure above, abcd is the larger square, we want to cut from it a square of length of the side de. Draw an arc of length ef from f to g. Now dg is the length of the square which is arrived after subtracting from square abcd and square of length de.
This is nothing but what is also known as Pythagoras theorem.