equilateral triangle = all sides are = in length
perimeter= the sum of all the side lengths
If the original triangle has a side length of x+4, then the smaller triangle has sidelengths of x.
Perimeter of small triangle= 27in
27in= x+x+x
27=3x
x=9inches
x+4= original side length
(9)+4= l
Original side length= 13inches
Answer: 13 inches.