PM+PN=MN
[tex]\frac{PM}{PN} =\frac{4}{5} => PM=4k , PN=5k[/tex] unde k este rezultatul raportului (coeficient de proportionalitate)
Atunci avem: MN=PM+PN=4k+5k=9k
a) [tex]\frac{PN}{PM}=\frac{5k}{4k}=\frac{5}{4}[/tex]
b) [tex]\frac{PN}{MN}=\frac{5k}{9k}=\frac{5}{9}[/tex]
c) [tex]\frac{MN}{PN}=\frac{9k}{5k}=\frac{9}{5}[/tex]
d) [tex]\frac{PM}{MN}=\frac{4k}{9k}=\frac{4}{9}[/tex]
