The area of a trapezoid is 78 square meters, its upper base is 11 meters, and its lower base is 15 meters. Find the height of the trapezoid.
一个梯形的面积是78平方米，它的上底是11米，下底是15米，求梯形的高．
<gadget id="calculator">39 / 26</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>