SOLUTION: The question I am doing now says "Find the measure of the unknown side" and it shows a picture of a triangle, it says side a is 13mm, side c is 5mm and you're trying to find side b

Algebra ->  Pythagorean-theorem -> SOLUTION: The question I am doing now says "Find the measure of the unknown side" and it shows a picture of a triangle, it says side a is 13mm, side c is 5mm and you're trying to find side b      Log On


   

Question 647498: The question I am doing now says "Find the measure of the unknown side" and it shows a picture of a triangle, it says side a is 13mm, side c is 5mm and you're trying to find side b. I know how to do pythagorean therom when you need to find side c, but how do you do it when you need to find side b?
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
You know this version of the Pythagorean theorem, the one with the + sign.

c² = a² + b²

But there are two other equivalent versions of it, and they have minus signs:

a² = c² - b²

and also

b² = c² - a²

So when you are finding c you use a plus + and if you're finding a or b,
you use a minus - .

Edwin