How do you find diagonals of a rectangle? are they the lines that go from corner to corner across the middle?

Question

landon34 · Answer

Yes I think that is true.

anonymous · Answer

You can use pythagorean theorem
And yes that is true

anonymous · Answer

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ram231 · Answer

is the pythagorean theorem basically like a2+b2=c2? 

And i have the length of 36 and diagonals of 39.

anonymous · Answer

If you know the 2 legs you know the diagonals.

anonymous · Answer

So to do that problem you would rearrange the equation to c^2-a^2=b^2

ram231 · Answer

how do I find the area though? thats the confusing part

anonymous · Answer

Once you get the other leg it's just length x width

ram231 · Answer

I'm confused. so I have the length of 36 and the hypotenuse of 39. so I just do 39^2 - 36^2 and that answer would be the other length and then I would just have to do length x width?

anonymous · Answer

Well after you do 39^2-36^2 you would take the square root of that and that would give you the leg and the rest is correct

ram231 · Answer

ok. ill try it

ram231 · Answer

I still don't get it....

ram231 · Answer

@zepdrix

anonymous · Answer

because $$39^2-36^2=c^2\rightarrow225=c^2$$ so to get c you would have to take the square root

ram231 · Answer

okay is it 540?

anonymous · Answer

Yes it is

anonymous · Answer

Sorry that equation was a bit confusing should've said b instead of c

anonymous · Answer

Make sure you put 540 units squared

ram231 · Answer

well it only gives me a choice of 540. I can't square it.