The inner circumference of a ring is 18.84cm, the ring width is 2cm, what is the area of the ring?
一个圆环内圆周长是18.84cm，环宽2cm，环形的面积是多少．
<gadget id="calculator">18.84 / 3.14 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">25 - 9</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>