Use mats to form a cylindrical grain storehouse with a ground circumference of 18.84 meters. How big is this food store?
用席子围成一个地面周长是18.84米的圆柱形粮囤．这个粮囤占地面积有多大？
<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>