The perimeter of an aquarium is 100.48 meters. In order to expand the scale, expand it into a fish pond with a diameter of 40 meters. How many square meters is the increased water area?
一个养鱼池周长是100.48米，为了扩大规模，将它扩建成直径为40米的养鱼池，求增加的水域面积是多少平方米？
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">100.48 / 3.14 / 2</gadget>
<output>16</output>

<gadget id="calculator">16 ** 2</gadget>
<output>256</output>

<gadget id="calculator">3.14 * 256</gadget>
<output>803.84</output>

<gadget id="calculator">1_256 - 803.84</gadget>
<output>452.16</output>

<result>452.16</result>