Răspuns :
Formula: Perimetrul Dreptunghiului = 2(l+L)
a) P = 2(12) = 24 (cm)
b) P = 2(15) = 30 (cm)
c) P = 2(15) = 30 (mm)
[tex]\it a)\ \ \mathcal{P}=2(L+\ell)=2(8+4)=2\cdot12=24\ cm\\ \\ \\ c)\ \ \mathcal{P}=2(L+\ell)=2(10+5)=2\cdot15=30\ mm=3\ cm[/tex]