There are 10 round wooden columns in the school corridor. The circumference of each wooden column is 9.42 decimeters and the height is 3 meters. If these wooden columns are to be painted once, what is the total area to be painted?
学校走廊共有10根圆木柱，每根木柱的底面周长是9.42分米，高3米．若要将这些木柱都油漆一遍，需油漆的总面积是多少平方分米．
<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<gadget id="calculator">9.42 * 30 * 10</gadget>
<output>2_826</output>

<result>2_826</result>