There is a cuboid tank whose bottom is a square with a side length of 20 cm. A section of cuboid steel block with a cross-sectional area of 60 cm2 is immersed in it. When the steel block is taken out of the water, the water in the tank drops by 3 cm. Find the length of this piece of steel.
有一个长方体水槽，它的底面是边长为20厘米的正方形，有一段横截面面积为60平方厘米的长方体钢块浸没其中，当钢块从水中取出后，水槽中的水下降了3厘米，求这段钢块的长．
<gadget id="calculator">3 / 60</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">20 * 20 * (1/20)</gadget>
<output>20</output>

<result>20</result>