If a wire is 10 decimeters long and rotates around one end of the circle, what is the area swept by the wire?
一根铁丝长10分米，以它的一端点为圆心旋转一周，这根铁丝扫过的面积是多少平方分米？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>