In a cylindrical bucket, put a piece of round steel with a radius of 5 cm into the water, the water level will rise by 12 cm, and when the round steel is pulled out of the water for a length of 8 cm, the water level will drop by 4 cm. Find the volume of the round bar?
在一个圆柱形的水桶里，把一段半径是5厘米的圆钢全部放入水中，水面就上升12厘米，把圆钢竖着拉出水面8厘米长后，水面就下降4厘米．求圆钢的体积？
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 25 * 2 * 12</gadget>
<output>1_884</output>

<result>1_884</result>