A trapezoidal vegetable field has an area of 144 square meters, its upper base is 15 meters, and its lower base is 17 meters. What is the height in meters?
一块梯形菜地面积是144平方米，它的上底是15米，下底是17米，高是多少米．
<gadget id="calculator">15 + 17</gadget>
<output>32</output>

<gadget id="calculator">2 / 32</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">144 * (1/16)</gadget>
<output>9</output>

<result>9</result>