11. Cost of heron's formula

Find the area of a triangular park, two of which sides are 10 \(m\) and 11 \(m\), and the perimeter is 30 \(m\). Also, find the cost of levelling the field at a rate of \(₹\)20 per square metre? (Use \(\sqrt{2} = 1.41\))

 

Area of the triangular park \(=\)  \(m^2\)

 

Cost of levelling the park \(=\) \(₹\)

 

[Note: Round off the area up to two decimal places and round off the cost to the whole number.]