If the diameter of the circle on which an arc is located is 12 cm, what is the length of the arc subtending a central angle of 45° in cm?
一条弧所在的圆的直径是12厘米，那么45°圆心角所对的弧长为多少厘米．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">45 * 3.14 * 6</gadget>
<output>847.8</output>

<gadget id="calculator">847.8 / 180</gadget>
<output>4.71</output>

<result>4.71</result>