A steel pipe with a length of 1m has a cross-section with an outer diameter of 8cm and an inner diameter of 4cm. What is the volume of this steel pipe in cm**3.
一根长1m的钢管，横截面的外直径是8cm，内直径是4cm，这根钢管的体积是多少cm**3．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

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

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

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

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<gadget id="calculator">3.14 * 12 * 1 * 100</gadget>
<output>3_768</output>

<result>3_768</result>