The sides of a triangular park are 35 m, 53 m and 66 m. The cost of levelling the park at the rate of ₹9.25/ m$^2$ is:

₹8,547

We have,

Side of the triangle are  = 35, 53, 66

Semi perimeter = \(\frac{(35 + 53 + 66) }{2}\) = 77

Area = \(\sqrt {s(s-a)(s-b)(s-c) }\)

= \(\sqrt {77(77-35)( 77-53)( 77-66) }\)

= \(\sqrt {77(42)( 24)( 11) }\)

= 924m²

The cost of leveling the park at the rate of ₹9.25/m² is = 9000 ×7.4 =  ₹8,547