There is a trapezoidal vegetable field, the upper base is 15 meters, the lower base is 35 meters, and the height is 20 meters. If 8.5 kilograms of vegetables are harvested per square meter, how many kilograms of vegetables can be harvested in this field?
有一块梯形菜地，上底是15米，下底是35米，高是20米，如果每平方米收菜8.5千克，这块地可收菜多少千克？
<gadget id="calculator">15 + 35</gadget>
<output>50</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">50 * 10 * 8.5</gadget>
<output>4_250</output>

<result>4_250</result>