The upper base of a trapezoid is 6 cm long, the lower base is 9 cm long, the height is in cm, and the area is 45 cm2.
一个梯形上底长6厘米，下底长9厘米，高多少厘米，面积是45平方厘米．
<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">45 * (2/15)</gadget>
<output>6</output>

<result>6</result>