State and prove Pythagoras theorem !!!!!
Answers
STATEMENT :-
- Pythagoras theorem states that “ In a right-angled triangle, the square of the hypotenuse side is equal to the sum of squares of the other two sides”. The sides of the right-angled triangle are called base, perpendicular and hypotenuse . Proof: Given, a triangle ABC in which ∠ABC is 900.
PROOF :-
We know, △ADB ~ △ABC
Therefore, AD/AB = AB/AC (corresponding sides of similar triangles)
Or, AB2 = AD × AC ……………………………..……..(1)
Also, △BDC ~△ABC
Therefore, CD/BC = BC/AC (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.
Statement: In a right angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
Given: ABC is a triangle in which ∠ABC=90
∘
Construction: Draw BD⊥AC.
Proof:
In △ADB and △ABC
∠A=∠A [Common angle]
∠ADB=∠ABC [Each 90
∘
]
△ADB∼△ABC [A−A Criteria]
So,
AB/AD=AC/AB
Now, AB ^2=AD×AC ..........(1)
Similarly,
BC ^2=CD×AC ..........(2)
Adding equations (1) and (2) we get,
AB^2 +BC^2 =AD×AC+CD×AC
=AC(AD+CD)
=AC×AC
∴AB^2 +BC^2 =AC^2
[henceproved]