Question

$25mm$ is equal to how many $cm$?

Answer 1

$25mm=2.5cm$
Explanation:
Using the related conversion
That is $1cm=10cm$
$25mm=(2\ast 10mm)+(\frac{1}{2}\ast 10mm)$
So, we have $2+\frac{1}{2}cm=2\frac{1}{2}=2.5cm$
or using ratio method
$\frac{1cm}{10mm}=\frac{x\cdot cm}{25mm}$ required to calculate value of $x$
using cross multiplication:
$10x=25$
$x=\frac{25mm}{10mm}=2.5cm$