1.Perimetru dreptunghi=60cm,
L=2×l,
P=2×L+2×l,
P=2×2l+2l,
P=6l
60=6l,
l=60:6=10cm,deci latura patrat=10cm
Perimetrul patratului=4×l=4×10=40cm
2.L=24cm,
l=L÷3,
P=2×L+2×l,
P=2L+2L÷3,
P=6L+2Ltotul supra 3
P=8L/3
P8×24supra3,
P=64cm
3.notamAB cu a,AC cu a+1 si cu a+2,
P= a+a+1+a+2
P=3a+3
24=3a+3
3a=24-3
3a=21
a=21÷3,
a=7
deci AB=7,AC=8,BC=9.