What is the circumference of a semicircular piece of paper with a radius of 12 cm?
一个半径为12厘米的半圆形纸片，它的周长是多少厘米．
<gadget id="calculator">3.14 * 12</gadget>
<output>37.68</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">37.68 + 24</gadget>
<output>61.68</output>

<result>61.68</result>