The area of a trapezoid is 36 square meters and the height is 4 meters. What is the sum of the upper and lower bases in meters?
一个梯形的面积是36平方米，高是4米，上底和下底的和是多少米．
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">36 * (1/2)</gadget>
<output>18</output>

<result>18</result>