The radius of the base of a semi-cylindrical is 4 cm. Divide the semi-cylindrical into several equal parts along the radius of the base, and put together an approximate cuboid with the same base and height as the original semi-cylindrical. The sum of the areas of the front, back, left and right sides of this cuboid is 102.8 square centimeters. What is the volume of the original half cylinder in cubic centimeters?
一个半圆柱的底面半径是4厘米，把这个半圆柱沿底面半径分成若干等份，拼成一个原来半圆柱等底等高的近似长方体．这个长方体的前、后、左、右四个面的面积和是102.8平方厘米．原来半圆柱的体积是多少立方厘米．
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 4 * 1</gadget>
<output>12.56</output>

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

<gadget id="calculator">12.56 + 8</gadget>
<output>20.56</output>

<gadget id="calculator">102.8 / 20.56</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 8 * 5</gadget>
<output>125.6</output>

<result>125.6</result>