What is the circumference of a semicircle with a diameter of 6 cm
一个直径是6厘米的半圆，周长是多少厘米
<gadget id="calculator">3.14 * 6</gadget>
<output>18.84</output>

<gadget id="calculator">18.84 / 2</gadget>
<output>9.42</output>

<gadget id="calculator">9.42 + 6</gadget>
<output>15.42</output>

<result>15.42</result>