There is a cylindrical oil tank with a height of 8dm. Now it needs to be heightened by 5dm, so that the surface area increases by 6.28m**2. What is the volume of the oil tank after it is heightened?
有一个圆柱形油罐，高8dm，现在需要加高5dm，这样表面积增加6.28m**2，油罐加高后的体积是多少立方米？
<gadget id="calculator">6.28 / 5</gadget>
<output>1.256</output>

<gadget id="calculator">1.256 / 3.14 / 2</gadget>
<output>0.2</output>

<gadget id="calculator">0.2 ** 2</gadget>
<output>0.04</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">3.14 * 0.04 * 13</gadget>
<output>1.6328</output>

<result>1.6328</result>