A triangular plot is such that two of its sides, of lengths 90m (meter) and 60m, are perpendicular to each other. There is a housing complex in a rectangular region within the plot. The area of the rectangular region is 4/9th of the area of the triangular plot. Additionally, two sides of the rectangular region lie on the two perpendicular sides of the triangle, and one vertex is on the hypotenuse. The members of the housing complex want to construct a wall along the perimeter of the rectangular region.
If the cost of construction is Rs. 5000/m, what is the MINIMUM possible cost of building the wall?