two sides of a triangle have the same length. the third side measures 2m less than twice the common length. the perimeter is 1.8m. what are

Let the common length be x. Then the perimeter is 2x + (2x-2) or 4x-2, so we must have 4x-2 = 1.8

$${\mathtt{x}} = {\frac{\left({\mathtt{1.8}}{\mathtt{\,\small\textbf+\,}}{\mathtt{2}}\right)}{{\mathtt{4}}}} = {\mathtt{x}} = {\mathtt{0.95}}$$ metres

 The third side is then 2*0.95 - 2 which is less than zero!  So there is a problem with the question specification!