A semi-circular flower bed needs to be surrounded by a bamboo fence, and the radius of the semi-circular flower bed is 5 meters. How many meters of fence is needed (π takes 3.14).
一个半圆形花坛的四周要围一圈竹篱笆，半圆形花坛的半径为5米，需要围多少米米篱笆(π取3.14)．
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">3.14 * 2 * (5/2)</gadget>
<output>15.7</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">15.7 + 10</gadget>
<output>25.7</output>

<result>25.7</result>