The upper base of an isosceles trapezoid is 5 cm, the lower base is 9 cm, and the length of a waist is 8 cm. How many decimeters of iron wire are needed to enclose this isosceles trapezoid.
一个等腰梯形的上底是5厘米，下底是9厘米，一条腰长8厘米，围成这个等腰梯形至少要多少分米的铁丝．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">5 + 9 + 16</gadget>
<output>30</output>

<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<result>3</result>