Question

State 7m to 250cm as a ratio in its lowest terms

Answer 1

First you have to convert the numbers to the same units.  Either m to cm or cm to m.
To go from meters to centimeters you multiply the number by 100.
7*100=700cm
Now you have 700cm/250cm.  This needs simplified
I divided each number by 50 to get 14 and 5
14cm/5cm or 14cm:5cm