A cylindrical container is filled with water. Measured from the inside, the bottom area is 42 cm2 and the height is 30 cm. At this time, the water surface is 20 cm high. If a conical cast iron part with a bottom area of 36 cm2 is put into the water, the water surface will be 26 cm, how many centimeters is the height of the conical cast iron part?
一个圆柱体容器内装有水，从里面量，底面积为42平方厘米，高30厘米，此时水面高20厘米，若将底面积为36平方厘米的圆锥形铸铁零件放入水中，则水面高26厘米，求圆锥形铸铁零件高多少厘米？
<gadget id="calculator">26 - 20</gadget>
<output>6</output>

<gadget id="calculator">42 * 6</gadget>
<output>252</output>

<gadget id="calculator">3 / 36</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">252 * (1/12)</gadget>
<output>21</output>

<result>21</result>