trapezoid has an upper base of 15 cm, a lower base of 25 cm, an area of 120 cm2, and its height in cm.
一个梯形，上底是15厘米，下底是25厘米，面积是120平方厘米，高是多少厘米．
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

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

<gadget id="calculator">120 * (1/20)</gadget>
<output>6</output>

<result>6</result>