The expanded side view of a cylinder is a rectangle with a side length of 6.28 cm. What is the area of the base of the cylinder?
圆柱侧面展开图是一个边长为6.28厘米的长方形，这个圆柱的底面积是多少．
<gadget id="calculator">6.28 / 3.14 / 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>