You can put this in proportion form. 29 is the whole, so you would have 29 / 100. 3 is only part of it, and you want to know what is the percent for 3, so you would have 3 / x (Or any other variable is fine.)
29 / 100 = 3 / x
Cross multiply and you would get 29x = 300. Divide 300 by 29, and you would get the answer, which is 10.35. The answer would be x = 10.35.
