A 13-meter-long rope has 44 centimeters left after wrapping 4 times around a cylindrical pillar. Find the radius of the cylinder.
一根13米长的绳子，绕一根圆柱形柱子4圈后还剩44厘米，求这根圆柱的半径．
<gadget id="calculator">13 - 0.44</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 / 4 / 2 / 3.14</gadget>
<output>0.5</output>

<result>0.5</result>