x = 10
since GI bisects ∠DGH then ∠DGI = ∠IGH, hence
2x - 13 = x - 3 ( subtract x from both sides )
x - 13 = - 3 ( add 13 to both sides )
perimeter means add the side
(x+4) +( x+8)+(2x-3) =P
x+x+2x+4+8-3=P
4x-9 =P