The area of a trapezoid is 18 square meters, the sum of the upper and lower bases is 9 decimeters, what is the height of the trapezoid?
一个梯形的面积是18平方米，上下底之和是9分米，梯形的高是多少．
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">18 * 100 * (2/9)</gadget>
<output>400</output>

<result>400</result>