Calculus problem

I really need help on this question. A goldsmith makes a wedding band by taking a gold ball and drilling a wide hole through it. The wedding band has to be 1 cm wide and the hole has to have a diameter of 2 cm. Given that gold weighs 19.32g/cm^3, how heavy will the wedding band be? There is actually a diagram to come with it, but i can't paste web addressess here. the equation i came up with is V = 2pi integral{0 to 1/2} (1 - x)dx and then mass = (volume)(19.32g/cm^3) does this seem right? does 2.529 g seem right to my problem? No, the formula to use is V=4/3 * pi * h where h = .5 V = approx. 0.52359 cm, so multiply that by the density. mass = 0.52359 cm * 19.32g/cm3 = approx 10.12gm