3. Pythagoras
Pythagoras was an ionic greek philosopher
mathematician . Pythagoras made
influential contributions to philosophy and
religion in the late 6h century BC .He is
often rewarrd as a great mathematician and
scientist and is best for the known
Pythagoras theorem.
4. Biography
Pythagoras was born in Samos and likely went to Egypt
and Babylon as a young man. He emigrated to southern
Italy about 532 bce, apparently to escape Samos's
tyrannical rule, and established his ethico-political
academy at Croton (now Crotone, Italy)
5. Early life
• Pythagoras spent most of his early childhood at Samos. At first
studied from the scholars of Syria.
• His meeting with Thales elicited in him an interest in science ,
mathematics and astronomy.
• He then went to Babylon and began to study mathematics.
6. Later life
The pythagoreans , as the followers of Pythagoras were called
.They lived and worked at the school.
Like most geniuses, Pythagoras too created many enemies .
One of them instigated the mob against the Pythagoreans and
set fire to the building where they ere staying . However
,Pythagoras was able to escape . He then went to Metpontum
and starved himself to death.
7. Pythagoras and Music
Pythagoras made important developments in music and astronomy.
Observing that plucked strings of different tones, he came up with
gave off different tones , he came up with the musical scale still
used today.
Was an accomplished musician at playing the lyre.
8. Pythagoras Theorem
T states that the square of the hypotenuse (the side
opposite the right angle) is equal to the sum of the
squares of the other two sides.
Hypotenuse2 = Perpendicular2 + Base2
c2 = a2 + b2
9. Proof Of Pythagoras theorem
A right-angled triangle ABC, right-angled at B.
To Prove- AC2 = AB2 + BC2
Construction: Draw a perpendicular BD meeting AC at D
Proof:
We know, △ADB ~ △ABC
Therefore, ADAB=ABAC (corresponding sides of similar triangles)
Or, AB2 = AD × AC ……………………………..……..(1)
Also, △BDC ~△ABC
Therefore, CDBC=BCAC (corresponding sides of similar triangles)
Or, BC2= CD × AC ……………………………………..(2)
Adding the equations (1) and (2) we get,
AB2 + BC2 = AD × AC + CD × AC
AB2 + BC2 = AC (AD + CD)
Since, AD + CD = AC
Therefore, AC2 = AB2 + BC2
Hence, the Pythagorean theorem is proved
10. Application of Pythagoras theorem
To know if the triangle is a right-angled triangle or not.
In a right-angled triangle, we can calculate the length of any side if
the other two sides are given.
To find the diagonal of a square.