The upper base of the trapezoid is 12 decimeters, and the lower base is equal to the height, which is 10 decimeters. What is its area?
梯形的上底是12分米，下底与高相等，都是10分米，它的面积是多少．
<gadget id="calculator">12 + 10</gadget>
<output>22</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">22 * 5</gadget>
<output>110</output>

<result>110</result>