http://i41.tinypic.com/rii6pt.jpg

I need help with part a. I don't understand how to write the formula. Please explain and show to me step by step on how to do this problem. Thanks.

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- Apr 6th 2010, 09:55 PMkrzyriceWriting a formula from a circle and triangle
http://i41.tinypic.com/rii6pt.jpg

I need help with part a. I don't understand how to write the formula. Please explain and show to me step by step on how to do this problem. Thanks. - Apr 6th 2010, 10:11 PMStroodle
To find $\displaystyle d$ you can use pythagorus' theorem. The hypotenuse is $\displaystyle x+r$, and the other side is $\displaystyle r$. Then note that $\displaystyle \theta=tan^{-1}\left ( \frac{d}{r} \right )$.

- Apr 6th 2010, 10:17 PMkrzyrice
What about theta in that formula? How would I find out what that is in order to find d?

- Apr 6th 2010, 10:25 PMStroodle
It's asking for $\displaystyle d$ in terms of $\displaystyle x$ and $\displaystyle r$. You don't need theta for this part of the question:

$\displaystyle d=\sqrt{(x+r)^2-r^2}$

You can simplify this formula.