A square cardboard with a side length of a meter, if you cut 4 equal and largest circles on this cardboard, what is the utilization rate of this cardboard?
一块边长为a米的正方形纸板，如果在这块纸板上剪4个相等且最大的圆，那么这块纸板的利用率是多少．
<gadget id="calculator">78.5 / 100</gadget>
<output>0.785</output>

<result>0.785</result>