A piece of rectangular paper with a length of 20 cm and a width of 15 cm is rotated around the long side as the axis to obtain a three-dimensional figure. What is its volume?
将一张长为20厘米、宽为15厘米的长方形纸以长边为轴，旋转一周，得到一个立体图形，它的体积是多少？
<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225 * 20</gadget>
<output>14_130</output>

<result>14_130</result>