Put a stone into a cylindrical container with a bottom radius of 5cm, and then fill it with water. After taking out the stone, the water level drops by 2cm. What is the volume of the stone?
把一块石头放进底面半径为5cm的圆柱形容器，然后加满水，取出石块后水面下降了2cm，求石头的体积是？
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

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

<result>157</result>