The sum of the upper and lower bases of a trapezoid is 36cm, and the height is 6cm. What is its area in cm**2.
一个梯形的上底与下底的和是36cm，高是6cm，它的面积是多少cm**2．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">36 * 3</gadget>
<output>108</output>

<result>108</result>