The circumference of a circle is 18.84 decimeters, what is the radius of the circle.
一个圆的周长是18.84分米，这个圆的半径是多少．
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">18.84 / 6.28</gadget>
<output>3</output>

<result>3</result>