The area of a trapezoid is 120 square decimeters, the height is 8 decimeters, its upper base is 11 decimeters, and its lower base is how many decimeters
一个梯形面积是120平方分米，高是8分米，它的上底是11分米，下底是多少分米
<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">120 * (1/4)</gadget>
<output>30</output>

<gadget id="calculator">30 - 11</gadget>
<output>19</output>

<result>19</result>