the complete question in the attached figure
we have that
b=8
H=13
H²=a²+b²----------------- >13²=a²+8²-- > a²=169-64------------ >a=10.25
Perimeter in actual sail=8+13+10.25=31.25 meters
scale factor=1/32
1 in the model -----------------------------32 in the actual
X-------------------------------------------31.25
x=31.25/32=0.9765 meters---------------- > 97.65 cms
the answer is
the perimeter of the sail on the model boat is 97.65 cms