After dividing a circle into two semicircles along the axis of symmetry, the circumference increases by 12 cm. What is the circumference of each semicircle in centimeters.
把一个圆沿对称轴分成两个半圆后，周长增加了12厘米．每个半圆的周长是多少厘米．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

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

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

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

<result>15.42</result>