cylindrical container with a bottom radius of 2 decimeters and a height of 4 decimeters is filled with water at a depth of 20 cm. Now put an irregular iron block into it. The iron block is completely submerged in the water, and the water level rises. 5 cm, what is the volume of this irregular piece of iron in cubic decimeters?
一个从里面量底面半径为2分米，高4分米的圆柱体容器中，装了深20厘米的水，现在往里面放入一个不规则的铁块，铁块完全浸入水中，水面上升了5厘米，这个不规则的铁块体积是多少立方分米？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 4 * (1/2)</gadget>
<output>6.28</output>

<result>6.28</result>