The sum of the upper and lower bases of a trapezoid is 14.4 decimeters, and the height is 3 decimeters. What is the area of the trapezoid in square decimeters?
一个梯形的上、下底的和为14.4分米，高是3分米，这个梯形的面积是多少平方分米．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">14.4 * (3/2)</gadget>
<output>21.6</output>

<result>21.6</result>