设圆锥底面半径为r，则2 * 3.14 * r = 18.84，所以r = 3圆锥的体积为V = 3.14 * r * r / 3 = 9.42立方米所以总重量为m = 0.75 * 9.42 = 7.065吨。
3.14*(18.84/3.14/2)*(18.84/3.14/2)*1/3*0.75=7.065吨
