The area of a trapezoidal flower bed is 36 square meters. It is known that the upper base is 4 meters and the lower base is 5 meters. How many meters is it high?
一个梯形花坛的面积是36平方米，已知上底是4米，下底是5米．高是多少米？
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">36 * (2/9)</gadget>
<output>8</output>

<result>8</result>