Răspuns:
Explicație pas cu pas:
ΔABC≈ΔDEF
AB/DE=BC/EF=AC/DF
AC=36 DF=30 ⇒AC/DF=36/30=6/5
metoda I a
P abc=24+30+36=90 cm
Pabc/Pdef=6/5 90/Pdef=6/5 Pdef=90·5/6=75 cm
metoda a doua
AB/DE=6/5 24/DE=6/5 4/DE=1/5 DE=20 cm
BC/EF=6/5 30/EF=6/5 EF=25 cm
Pdef=20+25+30=75 cm