00:01
We want to determine whether this is arithmetic, geometric, or neither.
00:03
So looking at the pattern here, it's clearly not arithmetic because we're not adding by the same amount each time.
00:11
It could be geometric, but we'd have to check.
00:13
If it is geometric, then the second term divided by the first term should give us the ratio.
00:20
So 5 divided by 2 is 2 .5.
00:23
And if it is, in fact, geometric, we have to check each term, 12 .5 divided by its preceding term, 5.
00:33
We would want to see if that is also 2 .5, and it is.
00:39
And we really should be checking throughout.
00:41
So let's just check the last one, 78 .125 divided by 31 .25.
00:51
And if it is equal to 2 .5, then we've got a common ratio...