17. Find the area of the walls

The walls of a living room are painted with identical triangular patterns. One such triangle has the vertices \((- 2, 1)\), \((- 9, -7)\) and \((5, 6)\). If the walls of the room are entirely covered by 130 triangles, then find the area of the walls.

 

 

Answer:

 

Area of the walls \(=\)  square units.