The upper base of a right-angled trapezoid is equal to the height, the lower base is 8 decimeters longer than the upper base by 2 decimeters, what is the area of the trapezoid in square decimeters?
一个直角梯形的上底与高相等，下底长8分米，比上底长2分米，梯形面积是多少平方分米．
<gadget id="calculator">8 - 2</gadget>
<output>6</output>

<gadget id="calculator">8 + 6</gadget>
<output>14</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">14 * 3</gadget>
<output>42</output>

<result>42</result>