The diameter of a round tablecloth is 1m, and the tablecloth is equipped with lace, what is the length of the lace in m
一张圆形桌布的直径是1m，给该桌布配上花边，花边长是多少m
<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>