A round steel with a length of 20cm is divided into two sections of the same length, and the surface area is increased by 20cm**2, what is the volume of the original steel?
一根长20cm的圆钢，分成一样长的两段，表面积增加20cm**2，原钢材的体积是多少．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 20</gadget>
<output>200</output>

<result>200</result>