A cylindrical oil tank was originally 8 decimeters high, but now it needs to be increased by 2 decimeters, so that the surface area increases by 62.8 square decimeters. What is the volume of the oil tank after the heightening?
一只圆柱形油罐，原来高8分米，现在需要加高2分米，这样表面积增加62.8平方分米，油罐加高后的容积是多少立方分米？
<gadget id="calculator">62.8 / 2</gadget>
<output>31.4</output>

<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

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

<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">3.14 * 25 * 10</gadget>
<output>785</output>

<result>785</result>