Răspuns :
triunghi echilateral = 3 laturi egale
triunghi isoscel = baza+2 laturi egale
P echi=P isos
P echi=4*3
P echi=12
P isos=12
Baza+2l=12
Baza=3
3+2l=12
2l=12-3
2l=9
l=9:2
l=4.5 cm
triunghi isoscel = baza+2 laturi egale
P echi=P isos
P echi=4*3
P echi=12
P isos=12
Baza+2l=12
Baza=3
3+2l=12
2l=12-3
2l=9
l=9:2
l=4.5 cm