what is 2.5 cm if it equals 0.1 km

What is 2.5 cm if 1cm equals 0.1 km ?

$$\small{\text{ $ \begin{array}{rcl} 1\ \mathrm{cm} & \widehat{=} & 0.1 \ \mathrm{km} \\ 2.5\ \mathrm{cm} & \widehat{=} & x \ \mathrm{km} \end{array} $ }}\\\\ \small{\text{ $\dfrac{1}{2.5} = \dfrac{0.1}{x} $}} \\\\ \small{\text{ $\dfrac{2.5}{1} = \dfrac{x}{0.1} $}} \\\\ \small{\text{ $ x=0.1\cdot \dfrac{2.5}{1} $}} \\\\ \small{\text{ $ x=0.25\ \mathrm{km} $}} \\\\$$