Răspuns :
p = 2×(l +L)
L = 1 dm = 10 cm
64 = 2× (l + 10)
l+10=32
l = 32-10
l = 22
L = 1 dm = 10 cm
64 = 2× (l + 10)
l+10=32
l = 32-10
l = 22
P=64 cm
latimea=1 dm=10 cm
Lungimea=?
P=L×2+l×2
P=L×2+10×2
P=L×2+20
64-20=44
44:2=22
Lungimea=22
Verificare
P=22×2+10×2
P=44+20
P=64cm
latimea=1 dm=10 cm
Lungimea=?
P=L×2+l×2
P=L×2+10×2
P=L×2+20
64-20=44
44:2=22
Lungimea=22
Verificare
P=22×2+10×2
P=44+20
P=64cm