Okay, here we have this:
Considering that the perimter is the sum of all the sides of the triangle we have the following formula:
Perimeter=a+b+c
a=a
b=1+a
c=5+a
Replacing with the provided info:
48=a+(1+a)+(5+a)
48=3a+6
3a=42
a=14
Now, according with this let's replace to find b and c:
b=1+a
b=1+14
b=15
c=5+a
c=14+5
c=19
Finally we obtain that the lenght of the sides of the triangle are 19 feet, 15 feet and 14 feet.
