Question

Summer looked at the formula for the Pythagorean Theorem, a2 + b2 = c2, she said that it didn’t matter which sides of a right triangle were a, b, and c. Is she correct?

Answer 1

Answer:

Summer is incorrect

Step-by-step explanation:

It definitely matters which side is side "c".  Side "c" must be the hypotenuse (the side across from the right angle).

The other two sides are the legs (sides touching the right angle), and either leg can be "a" or "b", but the hypotenuse must be "c".

Take the equation, a² + b² = c², and subtract c² from both sides:

$a^{2} +b^{2} -c^{2} =0$

It won't matter which leg is "a" or "b", because of the commutative property of addition.  Note that "a²" and "b²" are added together, and due to the commutative property of addition, we can add in either order and get the same result.

However, since the c² term is connected by subtraction, and subtraction doesn't have a commutative property, it can't be subtracted in any order.  Meaning which side it is is important.