Roll a rectangular iron sheet with a length of 15.7 decimeters and a width of 9.42 decimeters into a cylinder, and then add a circular iron sheet with a diameter of how many decimeters, can it be made into a cylindrical bucket with the largest volume without a cover?
将长15.7分米、宽9.42分米的长方形铁皮卷成一个圆柱，再配上直径是多少分米的圆形铁皮，可以做成一个容积最大的无盖的圆柱形水桶？
<gadget id="calculator">15.7 / 3.14</gadget>
<output>5</output>

<result>5</result>