There is a cuboid lead block in a cylindrical bucket. It is known that the bottom surface of the lead block is a square with a side length of 20cm. After the lead block is taken out, the water level drops by 6cm. If the bottom of the bucket has a radius of 20 cm, what is the height of the lead block in cm?
一个圆柱形水桶里有一个长方体铅块，已知铅块的底面是边长为20cm的正方形，取出铅块后水面下降了6cm．如果水桶的底面半径为20cm，则铅块高多少厘米？
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400 * 6</gadget>
<output>7_536</output>

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

<gadget id="calculator">7_536 / 400</gadget>
<output>471/25 = around 18.84</output>

<result>471/25 = around 18.84</result>