circular flower bed has a diameter of 9 meters, what is the area of the circular flower bed?
一个圆形的花坛直径为9米，那么这个圆形花坛的面积是多少．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">(9/2) ** 2</gadget>
<output>81/4 = around 20.25</output>

<gadget id="calculator">3.14 * (81/4)</gadget>
<output>63.585</output>

<result>63.585</result>