The bottom surface of a cylinder is divided into several sectors on average, and then cut and assembled into several sectors, and then cut and assembled to form an approximate cuboid. The surface area is increased by 200 square centimeters compared to the original. Given that the height of the cylinder is 20 cm, find the volume of the cylinder.
一个圆柱的底面平均分成若干个扇形，然后切开拼成若干个扇形，然后切开拼成一个近似的长方体，表面积比原来增加了200平方厘米．已知圆柱高20厘米，求圆柱的体积．
<gadget id="calculator">200 / 2 / 20</gadget>
<output>5</output>

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

<gadget id="calculator">3.14 * 25 * 20</gadget>
<output>1_570</output>

<result>1_570</result>