The diameter of a semicircle is 10 cm, what is the circumference in meters?
半圆直径10cm，周长多少米．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

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

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

<gadget id="calculator">25.7 / 100</gadget>
<output>0.257</output>

<result>0.257</result>