The circumference of the bottom of the cylinder is 6.28 decimeters, and the side expansion is a square, find the volume of the cylinder.
圆柱底面周长是6.28分米，侧面展开是一个正方形，求圆柱的体积．
<gadget id="calculator">6.28 / 3.14 / 2</gadget>
<output>1</output>

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

<gadget id="calculator">3.14 * 1 * 6.28</gadget>
<output>19.7192</output>

<result>19.7192</result>