Hi I was wondering if anyone could help me with this query.

Which is right to use out of these following examples?

The baker has a three slice smaller loaf or the baker has a three slices smaller loaf

He has a 5 centimetre shorter piece of string or he has a 5 centimetres shorter piece of string

John has a 10 foot taller roof or John has a 10 feet taller roof?

Thanks in advance