trapezoidal billboard with an upper base of 10 meters, a lower base of 18 meters and a height of 2 meters. Paint this billboard with a total of 56 kilograms of paint, how many kilograms of paint is used per square meter on average?
一个梯形广告牌，上底10米，下底18米，高2米．油漆这个广告牌一共用油漆56千克，平均每平方米用油漆多少千克？
<gadget id="calculator">56 / 28</gadget>
<output>2</output>

<result>2</result>