It is known that the upper base of a trapezoid is 6 meters, the lower base is 1.5 times the upper base, and the height is 2.4 meters. What is the area of this trapezoid?
已知一个梯形的上底是6米，下底是上底的1.5倍，高是2.4米，这个梯形的面积是多少．
<gadget id="calculator">6 * 1.5</gadget>
<output>9</output>

<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<gadget id="calculator">2.4 / 2</gadget>
<output>1.2</output>

<gadget id="calculator">15 * 1.2</gadget>
<output>18</output>

<result>18</result>