The cost of levelling the ground in the form of a triangle having the sides `51 m`, `37 m` and `20 m` at the rate Rs `3` per `m^(2)` is

Options

A. Rupee `918`
B. Rupee `908`
C. Rupee `910`
D. Rupee `898`

Answer

A

Explanation

Let sides of a triangle be `a =51m, b=37 m` and `c =20 m`
Now, semi-perimeter of triangle.
`s=(a+b+c)/(2)=(51+37+20)/(2)=(108)/(2)=54m`
`therefore" ""Area of triangle"=sqrt(s(s-a)(s-b)(s-c))" "["by Heron's formula"]`
`=sqrt(54(54-51)(54-37)(54-20)`
`=sqrt(54xx3xx17xx34)`
`=sqrt(9xx3xx2xx3xx17xx17xx2)`
`=3xx3xx2xx17=306m^(2)`
`because "Cost of levelling per "m^(2)="rupee "3`
`therefore"Cost of levelling per 306 " m^(2)=3xx306="rupee "918`