a room is 9 m long. 8m wide and 4m high. find the cost of plastering its wall and ceiling at the rate of RS 250 per square metre

The dimensions of the room are 

`l = 9 m, b = 8 m and h = 4 m `

To find the cost of plastering the walls and the ceiling we need to find the area of the four walls and the ceiling. The room is in cuboidal shape. 

Total surface area of the room = `2(lb + bh + hl)`

But here we should not consider the floor of the room.

So,...

The dimensions of the room are 

`l = 9 m, b = 8 m and h = 4 m `

To find the cost of plastering the walls and the ceiling we need to find the area of the four walls and the ceiling. The room is in cuboidal shape. 

Total surface area of the room = `2(lb + bh + hl)`

But here we should not consider the floor of the room.

So, the required area is `lb + 2bh + 2hl`

Required area = `9*8 + 2(8*4) + 2(4*9)`

                        =`72 + 64 + 72 = 208 m^2 `

The cost of plastering per square meter = Rs 250

The cost of plastering for 208 square meter =`250 X 208 = Rs.52,000`