2 сторона: 3/5+2/7=21/35+10/35=31/35
3сторона:31/35-9/14=62/70-45/70=17/70
периметр:3/5+31/35+17/70=42/70+62/70+17/70=121/70=1 51/70
2 сторона: 3/5+2/7=21/35+10/35=31/35
3сторона:31/35-9/14=62/70-45/70=17/70
периметр:3/5+31/35+17/70=42/70+62/70+17/70=121/70=1 51/70