A trapezoidal vegetable field has an upper base of 8 meters, a lower base of 12 meters, and a height of 10 meters. What is the area of this vegetable field in square meters?
一块梯形菜地的上底8米，下底12米，高10米．这块菜地的面积是多少平方米？
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>