The radius of a semicircle is 8 meters, what is the circumference of the semicircle?
一个半圆的半径是8米，这个半圆的周长是多少米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 8 * 1</gadget>
<output>25.12</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">25.12 + 16</gadget>
<output>41.12</output>

<result>41.12</result>