For a trapezoidal slope, the upper base is 15 meters, the lower base is 25 meters, and the height is 6 meters. If all grass is planted, how many square meters will the grass be planted on?
一块梯形坡地，上底是15米，下底是25米，高6米，如果全部种草，种草的面积是多少平方米？
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<result>120</result>