Let us assume the width of the rectangular room = x feet
then
Length of the rectangular room = x + 4 feet
Perimeter of the rectangular room = 38 feet
Then
Perimeter of the rectangular room = 2 ( length + Width)
38 = 2 [x + (x + 4)]
38 = 2 (2x + 4)
38/2 = 2x + 4
19 = 2x + 4
19 - 4 = 2x
15 = 2x
x = 15/2
= 7.5 feet
So the length of the rectangular room is 7.5 feet.
