There is a circular flower bed in the middle of a rectangular lawn with a length of 20 meters and a width of 12 meters. The measured circumference of the flower bed is 25.12 meters. How much area does the lawn occupy?
在一块长20米，宽12米的长方形草坪中间有一个圆形花坛，测得花坛的周长是25.12米．草坪占多大面积？
<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

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

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

<gadget id="calculator">240 - 50.24</gadget>
<output>189.76</output>

<result>189.76</result>