The upper base of a trapezoid is 16cm, the lower base is 24cm, the area is 80cm**2, and the height is cm.
一个梯形的上底是16cm，下底是24cm，面积是80cm**2，高是多少cm．
<gadget id="calculator">16 + 24</gadget>
<output>40</output>

<gadget id="calculator">2 / 40</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">80 * (1/20)</gadget>
<output>4</output>

<result>4</result>