[tex] \frac{6}{12} = \frac{2}{c} \\ \\ \frac{1}{2} = \frac{2}{c} \ / \ simplify \\ \\ \frac{1}{2} c = 2 \ / \ multiply \ each \ side \ by \ c \\ \\ \frac{c}{2} = 2 \ / \ simplify \\ \\ c = 2 \times 2 \ / \ multiply \ each \ side \ by \ 2 \\ \\ c = 4 \ / \ simplify \\ \\ [/tex]
The final result is c = 4.