A square aquarium has a circumference of 80 meters and a circular island in the middle with a diameter of 12 meters. How many square meters is the water area of this aquarium?
一个正方形养鱼池周长是80米，中间有一个圆形小岛，直径是12米，这个养鱼池的水域面积是多少平方米？
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<gadget id="calculator">400 - 113.04</gadget>
<output>286.96</output>

<result>286.96</result>