The ratio of the diameter of a cylinder to the base of a cone is 2:1, and the volume ratio is 4:1. If the height of the cone is 12 cm, what is the height of the cylinder in cm?
一个圆柱与圆锥底面直径之比是2：1，体积比是4：1，若圆锥的高是12厘米，圆柱的高是多少厘米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">12 * (1/3)</gadget>
<output>4</output>

<result>4</result>