An isosceles triangle is formed by an iron wire with a length of 18dm. If the length of the waist is 5dm, what is the length of the base in decimeters?
用一根长为18dm的铁丝围成一个等腰三角形，如果腰长为5dm，底边的长为多少分米？
<gadget id="calculator">18 - 5 - 5</gadget>
<output>8</output>

<result>8</result>