In a cylindrical bucket with a bottom radius of 15cm, a piece of cylindrical steel with a diameter of 10cm is completely submerged in water. After the steel is taken out of the bucket, the water level in the bucket drops by 3cm. Find the length of this piece of steel.
在一个底面半径是15cm的圆柱形水桶里，有一段直径为10cm的圆柱形钢铁完全浸没在水中，把钢铁从桶里取出后，桶里的水面下降了3cm，求这段钢铁的长．
<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225 * 3</gadget>
<output>2_119.5</output>

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

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

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">2_119.5 / 78.5</gadget>
<output>27</output>

<result>27</result>