Related Rates setup issue

I'm having issues setting up a related rates problem. Mostly because it is talking about electricity and I'm not all that sure about how to visualize it.

Quote:

The impedance Z(ohms) in a series circuit is related to the resistance R(ohms) and reactance X(ohms) by the equation $\displaystyle \sqrt[]{R^2+X^2}$. If R is increasing at 3 ohms/sec and X is decreasing at 2 ohms/sec, at what rate is Z changing when R=10 ohms and X=20 ohms?

If I could just have some help with setting this up I would be very grateful.

Thanks