The diameter of a circle is 4 centimeters, how many centimeters should the two legs of the compass be apart when drawing a circle?
一个圆的直径是4厘米，画圆时圆规两脚应叉开多少厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<result>2</result>