In a rectangle whose length is 4 cm and width is 2 cm, draw the largest circle and find the area of the circle.
在一个长是4厘米，宽是2厘米的长方形中，画出一个最大的圆，并求出这个圆的面积．
<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>