Here, we first find the area of the triangular side walls.

a = 122 m, b = 120 m and c = 22 m

∴ s = 122 + 120 + 22 /.2 m = 132 m

Rent of 1 m^{2} of the wall for 1 year = Rs 5000

∴ Rent of 1 m^{2} of the wall for 1 month = Rs 5000/ 12

∴ Rent of the complete wall (1320 m^{2}) for 3 months

= Rs 5000/ 12 × 1320 × 3 = **Rs 16,50,000 Ans.**