In a circle with a diameter of 3 cm, what is the length of the arc subtended by a central angle of 120°?
在直径为3厘米的圆中，120°圆心角所对的弧长是多少厘米．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">120 * 3.14 * (3/2)</gadget>
<output>565.2</output>

<gadget id="calculator">565.2 / 180</gadget>
<output>3.14</output>

<result>3.14</result>