If 60 seconds are in a minute , 60 minutes in a hour and 24 hours in a day, than 86,400 seconds are in a day. what type of reasoning g is this?

The type of reasoning is deductive.

Deductive reasoning is the use of logic process to derive valid conclusions from a set of premises that are considered true.

In this case the premises that are considered true are:

1)  There are 60 seconds in a minute,

2) There are 60 minutes in an hour, and

3) There are 24 hours in a day

The logical process is:

From premise 1: 1 day = 24 hours

From premise 2: 24 hours = 24 * 60 minutes

From premise 3: 24*60 minutes = 24*60*60 seconds = 86,400 seconds

Conclusion: 1 day = 86,400 segundos.

deductive