There are 8 cylindrical wooden piles in the hall that need to be painted. The circumference of the bottom of the wooden piles is 2.5 meters and the height is 4.2 meters. 1 kg of paint can paint 6 square meters. How much paint is needed to paint these wooden piles?
大厅里有8根圆柱形木桩要刷油漆，木桩底面周长2.5米，高4.2米，1千克的油漆可以漆6平方米，那么刷这些木桩要多少油漆？
<gadget id="calculator">2.5 * 4.2</gadget>
<output>10.5</output>

<gadget id="calculator">10.5 * 8</gadget>
<output>84</output>

<gadget id="calculator">84 / 6</gadget>
<output>14</output>

<result>14</result>