Answer
There is a common difference of $1.7$ therefore the given terms form an arithmetic sequence.
Work Step by Step
The given terms can be terms of an arithmetic sequence if there is a common difference among consecutive terms.
Determine the difference between each pair of consecutive terms to obtain:
$4.3-2.6=1.7;
\\6.0-4.3=1.7;
\\7.7-6.0=1.7$
There is a common difference of $1.7$ therefore the given terms form an arithmetic sequence.