The diameter of a semicircle is 10 decimeters, what is the circumference of the semicircle?
一个半圆的直径10分米，这个半圆的周长多少分米？
<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>

<result>25.7</result>