A cylinder, if its height is truncated by 3cm, the surface area will be reduced by 94.2cm**2. What is the diameter of the base of this cylinder in centimeters?
一个圆柱，如果把它的高截去3cm，表面积就会减少94.2cm**2．这个圆柱的底面直径是多少厘米？
<gadget id="calculator">94.2 / 3</gadget>
<output>31.4</output>

<gadget id="calculator">31.4 / 3.14</gadget>
<output>10</output>

<result>10</result>