Răspuns:
AB//CD => triungh MAB asemenea cu MDC =>
MD/MD+AD =CD/AB
MD/MD+16 =15/25
25MD =15(MD+16)
25MD =15MD+240
10MD =240
MD =24 cm =>AM =24+16 =40 cm
MC/MC+BC =CD/AB
MC/MC+20 =15/25
25MC =15(MC+20)
25MC =15MC+300
10MC =300
MC =30 cm
=>MB =30+30 =60 cm
P mab =40+25+60 =125 cm