The length of the living room is 24 feet.
Given:
Area = 360 ft²
Length = x
Width = 5/8 of x
Area = Length * Width
360 ft² = x * 5x/8
360 ft² = 5x²/8
8 * 360 ft² = 5x²
2880 ft² / 5 = x²
576 = x²
√576 = x
24 = x
To check:
360 ft² = 24 ft * (24 *5/8)
360 ft² = 24ft * 15 ft
360 ft² = 360 ft²