A large pine tree casts a shadow on the ground under the sunlight, which is approximately circular. Its circumference is about 18.84 meters. What is the approximate area of the shaded area?
一棵大松树在阳光的照射下，投在地上的阴影是一个近似的圆形．它的周长大约是18.84米．阴影部分的面积大约是多少平方米？
<gadget id="calculator">18.84 / 3.14 / 2</gadget>
<output>3</output>

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

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

<result>28.26</result>