The outer diameter of the mouth of a circular water tank is 2m. Now make a cover for the water tank. What is the minimum area of the cover in square meters?
一个圆形水缸口的外直径为2m，现在为这个水缸做一个盖子，这个盖子的面积至少是多少平方米？
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

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

<result>3.14</result>