trapezoidal billboard has an upper base of 4.7 meters, a lower base of 15.3 meters, and a height of 2.4 meters. Now to paint the front and back of this billboard, if 0.6 kg of paint is used per square meter, how many kg of paint is needed?
一块梯形广告牌它的上底是4.7米，下底是15.3米，高是2.4米．现在要粉刷这块广告牌的正反两面，如果每平方米用油漆0.6千克，需要多少千克的油漆？
<gadget id="calculator">4.7 + 15.3</gadget>
<output>20</output>

<gadget id="calculator">2.4 / 2</gadget>
<output>1.2</output>

<gadget id="calculator">20 * 1.2 * 2 * 0.6</gadget>
<output>28.8</output>

<result>28.8</result>