The upper base and height of a trapezoid are both 8cm, and the lower base is 10cm, what is its area in cm**2.
一个梯形的上底和高都是8cm，下底是10cm，它的面积是多少cm**2．
<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">18 * 4</gadget>
<output>72</output>

<result>72</result>