A rectangle length was 4 feet longer than triple the length of it width

Length is 48 ft

The perimeter of a rectangle is equal to the sum of all side's.

2 (lengths) + 2 (widths) = perimeter

Length=3x+4

Now given the perimeter of 140

3 (3x+4) + 3 (x) = 140

9x+12+3x=140

12x+12=140

12x=128

X = 10.7

10.7 is the width

Length=3x+4

Length = 3 (10.6) + 4

Length=31.8+4

Length=35.8

Answer = 35.8

This can only be answered if you were given a perimeter.