If the area of a semicircle is 6.28 square centimeters, what is the circumference of the semicircle?
一个半圆的面积是6.28平方厘米，则这个半圆的周长是多少．
<gadget id="calculator">2 / 1</gadget>
<output>2</output>

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

<gadget id="calculator">2 * 3.14 * 1</gadget>
<output>6.28</output>

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

<gadget id="calculator">6.28 + 4</gadget>
<output>10.28</output>

<result>10.28</result>