cylindrical water tank filled with water, the diameter of the bottom surface is 10dm, and there is a conical part with a bottom area of 20 square decimeters in the tank, which is completely submerged in the water. If it is taken out, the water level will drop by 2cm. What is the height of the shape.
一个装有水的圆柱形的水缸，底面直径是10dm，缸中有一个底面积是20平方分米的圆锥形零件，完全浸没在水中，如果将其取出，水面就下降了2cm，这个圆锥形的高是多少．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 2</gadget>
<output>157</output>

<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">157 * (3/20)</gadget>
<output>471/20 = around 23.55</output>

<result>471/20 = around 23.55</result>