The upper base of a trapezoid is 16 meters, the lower base is 24 meters, and the height is 30 meters. What is its area in square meters?
一个梯形的上底是16米，下底是24米，高30米，它的面积是多少平方米．
<gadget id="calculator">16 + 24</gadget>
<output>40</output>

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

<gadget id="calculator">40 * 15</gadget>
<output>600</output>

<result>600</result>