There is a trapezoidal vegetable field. Its upper base is 25 meters, its lower base is 30 meters, and its height is 30 meters. What is its area in meters?
有一块梯形的菜地，它的上底是25米，下底是30米，高是30米，它的面积是多少米？
<gadget id="calculator">25 + 30</gadget>
<output>55</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">55 * 15</gadget>
<output>825</output>

<result>825</result>