In a cylindrical water storage bucket, put a piece of round steel with a radius of 5 cm vertically. If you put it all into the water, the water level in the bucket will rise by 10 centimeters; if you put the round steel in the water out of the water by 12 centimeters, the water level in the bucket will drop by 6 centimeters. Find the length of this round steel?
在一个圆柱形储水桶里，竖直放入一段半径为5厘米的圆钢．如果把它全部放入水中，桶里的水面就上升10厘米；如果把水中的圆钢露出水面12厘米，桶里的水面就下降6厘米，求这段圆钢的长？
<gadget id="calculator">300 / 47.1</gadget>
<output>6.369427</output>

<gadget id="calculator">3.14 * 6.369427</gadget>
<output>20.000001</output>

<result>20.000001</result>