find the length of each side of each triangle. if the corresponding sides are proportional, the two triangles are similar.
use the distance formula:
DE=√{[-3-(-1)]²+(-1-3)²}=√20=2√5
EF=√36=6
DF=√32=4√2
DG=√45=3√5
GH=√81=9
DH=√72=6√2
DE/DG=2/3
EF/GH=6/9=2/3
DF/DH=4/6=2/3
DE/DG=EF/GH=DF/DH=2/3
the corresponding sides are proportional, so the two triangles are similar.