Divide the circle into several equal parts and cut them together to form an approximate rectangle. It is known that the width of the rectangle is 1 decimeter and the length is how many decimeters.
把圆分成若干等份，剪拼成一个近似的长方形，已知长方形的宽是1分米，长是多少分米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 1 * 2 * (1/2)</gadget>
<output>3.14</output>

<result>3.14</result>