Răspuns:
L- lungimea
l- latimea
L=3xl
P= 2xL + 2xl
P= 2x3xl + 2xl
P= 6xl + 2xl
P= 8xl=76.8 cm
=> l= P:8
l= 76.8:8
l= 9.6 cm
L= 3xl
L= 3x 9.6
L= 28.8 cm
ABCD dreptunghi
AB,CD-lungimi
AD,BC-latimi
AB=CD,AD=BC
P=2(AB+BC)=76,8cm
AB=3BC
inlocuim in suma:
2(3BC+BC)=76,8cm
4BC=38,4cm
BC=9,6cm=>AB=3BC=3×9,6cm=28,8cm
