trapezoidal vegetable field has an upper base of 20 meters, a lower base of 16 meters, and a height of 8 meters. This year, a total of 720 kilograms of carrots were harvested in this field. On average, how many kilograms of carrots are harvested per square meter?
一块梯形菜地，上底20米，下底16米，高8米，今年在这块地里一共收胡萝卜720千克，平均每平方米收胡萝卜少千克？
<gadget id="calculator">20 + 16</gadget>
<output>36</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">36 * 4</gadget>
<output>144</output>

<gadget id="calculator">720 / 144</gadget>
<output>5</output>

<result>5</result>