Area of a four wall of a room is 77 square meters . the

Area of a four wall of a room is 77 square meters . the length and breadth of room are 7.5 meters and 3.5 meters respectively . the height of the room is ?

Area of four walls = 2 x (l + b ) x h
⇒ 2 x (7.5 + 3.5 ) x h = 77 m²
⇒ h = 77 / (2 x 11) = 7/2
∴ h = 3.5 meters