Divide the bottom surface of a cylinder into several sectors on average, and then cut and assemble them into an approximate cuboid. The surface area is increased by 200cm**2. Given that the height of the cylinder is 20cm, what is the volume of the cylinder in cm**3.
把一个圆柱的底面平均分成若干个扇形，然后切开拼成一个近似的长方体，表面积比原来增加了200cm**2．已知圆柱的高是20cm，圆柱的体积是多少cm**3．
<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>