[SOLVED] error propagation: the approximation formula

I can't seem to get the right answer to this one, and I hope someone can tell me what I am doing wrong!

"You measure the radius of a circle to be 12 cm and use the formula A = pi(r^2) to calculate the area. If your measurement of the radius is accurate to within 3%, approximately how accurate (to the nearest percent) is your calculation of the area?

The problem is that the answer given in the back of the book is 0.06. So, where did I mess up? Thanks for the help!