One side is against a wall, and the other side is a semicircular chicken farm surrounded by a bamboo fence. The diameter of this semicircle is 6 meters. How long is the fence?
一个一面靠墙，另一面是用竹篱笆围城的半圆形养鸡场，这个半圆的直径是6米，篱笆长多少米？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 3</gadget>
<output>9.42</output>

<result>9.42</result>