The upper base of an isosceles trapezoid is 8 cm, the lower base is 12 cm, and the waist is 9 cm. How many centimeters of iron wire is required to enclose this isosceles trapezoid?
一个等腰梯形的上底是8厘米，下底是12厘米，腰是9厘米，围成这个等腰梯形至少要多少厘米长的铁丝．
<gadget id="calculator">8 + 12 + 9 + 9</gadget>
<output>38</output>

<result>38</result>