The radius of the bottom surface of a cylindrical container is 5 cm. An iron ball is placed in the container filled with water. The iron ball sinks completely in the water and the water level rises by 2 cm. What is the volume of this iron ball?
一个圆柱形容器的底面半径是5厘米，把一个铁球放入这个装有水的容器中，铁球完全沉入水中，水面升高2厘米．这个铁球的体积是多少？
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 2</gadget>
<output>157</output>

<result>157</result>