[tex] \displaystyle \frac{10}{12} = \frac{25}{x} [/tex]
[tex] \displaystyle x \cdot \frac{10}{12} = 25 [/tex]
[tex] \displaystyle 10x = 25 \cdot 12 [/tex]
[tex] \displaystyle x = \frac{300}{10} [/tex]
[tex] \displaystyle \boxed{x = 30} [/tex]
[tex] \displaystyle \boxed{x = 30} [/tex]