How Do X1 and X2 Determine Delta R in Advanced Mechanics?

[metalmagik]

http://img136.imageshack.us/img136/6353/mechanicsau9.jpg

I have this question for my WebAssign and I am not sure what to do with it. I thoght about how to use the X1 and X2 to get delta r but I really have no idea where to start. Please help! Much appreciated

 

[dicerandom]

Hint: Use the Pythagorean Theorem.

 

[metalmagik]

I used it and got 11,624.97312. I entered 11,624.97 into Webassign and it came out a wrong answer. Could someone tell me if this is the right answer and I am entering it wrong or if I completely did this wrong?

I found one leg of the small triangle at the top of the diagram by subtracting 4900-3200, and used X1 as the other leg..then uesd the pythagorean theorem.

 

[metalmagik]

nevermind, got the answer, thanks a lot. I've got another mechanics question if anyone's around.