A metal cone with a bottom diameter of 40 cm is submerged in a cylindrical glass with a bottom diameter of 80 cm. At this time, the water in the cup is 3 cm higher than the original. Find the height of the metal cylinder.
把一个底面直径为40厘米的金属圆锥体浸没在底面直径为80厘米的圆柱形玻璃杯内，这时杯中水比原来升高3厘米．求金属圆柱体的高．
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<gadget id="calculator">40 ** 2</gadget>
<output>1_600</output>

<gadget id="calculator">3.14 * 1_600 * 3</gadget>
<output>15_072</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">3 / 1_256</gadget>
<output>3/1_256 = around 0.002389</output>

<gadget id="calculator">15_072 * (3/1_256)</gadget>
<output>36</output>

<result>36</result>