Use a 36-meter-long fence to form a trapezoidal vegetable field with a height of 10 meters. What is the area of this vegetable field?
用36米长的篱笆靠墙围成一块梯形的菜地，高是10米，这块菜地的面积是多少？
<gadget id="calculator">36 - 10</gadget>
<output>26</output>

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

<gadget id="calculator">26 * 5</gadget>
<output>130</output>

<result>130</result>