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question about pythagorean theorem

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question about pythagorean theorem

by 12181900 » Fri Feb 03, 2012 7:33 pm
this is a dumb question but i need to know so that i don't make mistakes in the future.

the first time i saw pythagorean theorem i wanted to square root both sides so that i ended up with a + b = c , like i would with any other algebraic equation.

can anyone please tell me why this is wrong? and should i not do this in the future with similar algerbraic equations?

thanks for your help.
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by Anurag@Gurome » Fri Feb 03, 2012 7:40 pm
12181900 wrote:this is a dumb question but i need to know so that i don't make mistakes in the future.

the first time i saw pythagorean theorem i wanted to square root both sides so that i ended up with a + b = c , like i would with any other algebraic equation.

can anyone please tell me why this is wrong? and should i not do this in the future with similar algerbraic equations?

thanks for your help.
Pythagorean Theorem states that hypotenuse² = sum of the squares of the other two sides
If c = hypotenuse, and a and b are the other two sides, then c² = a² + b²
If you take square root on both sides, then c = √(a² + b²) and not c = a + b.

We can take an example, 5 = hypotenuse and 3 and 4 are the other two sides
Then 5² = 3² + 4²
Taking square root on left hand side = 5
Square root on right hand side = √(3² + 4²) = √(9 + 16) = √25 = 5
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by 12181900 » Fri Feb 03, 2012 7:47 pm
Thanks!
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by Anurag@Gurome » Fri Feb 03, 2012 7:47 pm
12181900 wrote:Thanks!
You are welcome.
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by ronnie1985 » Sat Feb 04, 2012 2:41 am
(a+b)^2 = (a+b)*(a+b) = a*a + a*b + b*a + b*b = a^2 + a*b + a*b +b^2 = a^2 +2a*b + b^2
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