Răspuns :
[tex] \frac{7}{11}= \frac{77}{ x^{2} } \\ \\ 7 x^{2} =11*77 \\ \\ 7 x^{2} =7*11*11 \\ \\ x^{2} =11*11 \\ \\ x=11[/tex]
7/11=77/x^2
produsul mezilor=produsul extremilor
7*x^2=77*11=7*11*11
x^2=11^2
x=11
produsul mezilor=produsul extremilor
7*x^2=77*11=7*11*11
x^2=11^2
x=11