cylindrical tank filled with water has a bottom diameter of 10dm. There is an iron block completely submerged in the water. If it is taken out, the water level will drop by 2cm. What is the volume of this iron block?
一个装有水的圆柱形的水缸，底面直径是10dm，桶中有一个铁块完全浸没在水中，如果将其取出，水面就下降了2cm，这个铁块的体积是多少？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

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

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3.14 * 25 * (1/5)</gadget>
<output>15.7</output>

<result>15.7</result>