The bottom of the trapezoid is 48cm, the top and height are half of the bottom, what is the area in cm**2.
梯形下底是48cm，上底和高都是下底的一半，面积是多少cm**2．
<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<gadget id="calculator">24 + 48</gadget>
<output>72</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">72 * 12</gadget>
<output>864</output>

<result>864</result>