Work out each map scale as a map ratio a) 1cm to 5km b) 2cm to 25km how do you work out the map scales as a map ratio? give a brief proper explanation < 3

1:500000
1cm:500000cm

2:250000
2cm:250000cm
1cm:125000cm

To get this you convert the km into cm as it is easier and then it becomes something like this 2cm : 250000cm
then divide or half to get to the simpler form like this 2cm divided by 2=1cm and 250000cm divided by 2= 125000cm 
then put into ratio is 1:125000