A piece of iron wire is 180 meters long, the first use of the full length (2/3), the second use of the length is equivalent to the first (3/4), the second use than the first How short is it?
一根铁丝长180米，第一次用去全长的(2/3)，第二次用去的长度相当于第一次的(3/4)，第二次用去的比第一次短多少？
<result>90</result>