Use mats to form a cylindrical grain storage with a bottom circumference of 25.12 meters. How big is this food store?
用席子围成一个底面周长是25.12米的圆柱形粮囤．这个粮囤占地面积有多大？
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<gadget id="calculator">25.12 / 6.28</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

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

<result>50.24</result>