The radius of the inner circle of a ring is 3dm, which is (1/2) the radius of the outer circle. What is the area of the ring?
一个圆环的内圆半径是3dm，是外圆半径的(1/2)，圆环的面积是多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / (1/2)</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

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

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">113.04 - 28.26</gadget>
<output>84.78</output>

<result>84.78</result>