If a circular flower bed with a diameter of 4 meters is widened by 1 meter, how many square meters will the area of the flower bed increase from the original?
将一直径4米的圆形花坛向周围扩宽1米，花坛的面积比原来增加了多少平方米？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

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

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">28.26 - 12.56</gadget>
<output>15.7</output>

<result>15.7</result>