school has a semicircular flower bed with an area of 56.52 square meters. For the sake of beauty, the flower bed should be surrounded by decorative railings. How many meters is the railing?
某学校有一个半圆形的花坛，面积为56.52平方米，为了美观，花坛的周围要围上装饰栏杆，栏杆多少米．
<gadget id="calculator">3.14 * 6</gadget>
<output>18.84</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">18.84 + 12</gadget>
<output>30.84</output>

<result>30.84</result>