semi-circular chicken farm with a diameter of 6 meters, one side is against the wall, and the other side is surrounded by a bamboo fence. How many meters is the fence?
一个半圆形养鸡场，直径6米，一面靠墙，另一面用竹篱笆围起来．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>