The circumference of the base of a cone is 25.12 decimeters. After cutting the cone in half from the apex along the height, the sum of the surface areas is 24 square decimeters larger than the surface area of the cone. What is the volume of the original cone in cubic decimeters ．
一个圆锥体的底面周长是25.12分米，从圆锥的顶点沿着高将它切成两半后，表面积之和比圆锥的表面积增加24平方分米，原圆锥体的体积是多少立方分米．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">25.12 / 3.14</gadget>
<output>8</output>

<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (1/4)</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">(1/3) * 3.14 * 16 * 3</gadget>
<output>50.24</output>

<result>50.24</result>