Răspuns:
a)
[tex] \frac{5}{2} = \frac{a}{4} = \frac{b + 3}{5} [/tex]
[tex]a = \frac{4 \times 5}{2} = 10[/tex]
[tex]b + 3 = \frac{10 \times 5}{4} \\ b = \frac{25}{2} - 3 \\ b = \frac{19}{2} [/tex]
b)
[tex]\frac{a}{3} = \frac{b}{4} = \frac{c}{5} = k[/tex]
a=3k; b=4k; c=5k
3k×4k×5k=480
[tex]60 {k}^{3} = 480 \\ {k}^{3} = 8 \\ k = 2[/tex]
a=6
b=8
c=10
