Bonsoir,
a)
[tex] \frac{a}{4} = \frac{8}{5} [/tex]
[tex]a = \frac{8 \times 4}{5} [/tex]
[tex]a = \frac{32}{5} [/tex]
a = 6,4.
b)
[tex] \frac{7}{b} = \frac{2}{3} [/tex]
[tex] \frac{b}{7 } = \frac{3}{2} [/tex]
[tex]b = \frac{7 \times 3}{2} [/tex]
[tex]b = \frac{21}{2} [/tex]
b=10,5
c)
[tex] \frac{11}{6} = \frac{c}{15} [/tex]
[tex] \frac{11 \times 15}{6} = c[/tex]
[tex] \frac{165}{6} = c[/tex]
c=27,5
Bonne nuit !