potrzebna tylko b na dzisiaj do 13:30

[tex]a=15 \ mm\\\\b=23 \ mm\\\\c=1 \ cm=10 \ mm\\\\d=2 \ cm=20 \ mm\\\\Ob=15+23+10+20=38+30=\boxed{68 \ mm}[/tex]
Zadanie
b)
a = 2 cm
b = 1 cm
c = 23 mm = 2,3 cm
d = 15 mm = 1,5 cm
Ob. = a + b + c + d
Ob. = 2 + 1 + 2,3 + 1,5 = 6,8 cm