a) AB=20 mm=2 cm
BC=1,2cm
AC=0,1 dm=1 cm
P=2+1,2+1=4,2 cm
b) AB=21 cm =0,21 m
BC =1300 cm=13 m
AC=0,1 hm=10 m
P=0,21+13+10=23,21 m
c) AB=0,25 hm =25 m
BC=3,10 dam =31m AC= 12 m
P=25+31+12=68 m
d) AB=2,8 dam
BC=11,5 m =1,15 dam
AC=1550 cm =1,55 dam
P=2,8+1,15+1,55=5,5 dam