A wire can form a semicircle with a radius of 3 cm. How long is this wire?
一根铁丝可以围成一个半径是3厘米的半圆．这根铁丝有多长？
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 3 * 1</gadget>
<output>9.42</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

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

<result>15.42</result>