Step 1

For a sequence to be an arithmetic progression it must follow the common difference procedure as.

\(a, b, c, d, e, .....\)

\(b - a = c - b = d - c = e - d =....\)

Step 2

For the given sequence, check whether it follows the common difference as suggested above.

\(11, 10.2, 9.4, 8.6, 7.8,....\)

\(10.2 - 11 = -0.8\)

\(9.4 - 10.2 = -0.8\)

\(8.6 - 9.4 = -0.8\)

\(7.8 - 8.6 = -0.8\)

Step 3

As it follows the common difference procedure therefore it can be concluded that the given sequence is an arithmetic sequence and common difference ‘d’ is calculated to be as.

\(d = 10.2 - 11\)

\(= -0.8\)

For a sequence to be an arithmetic progression it must follow the common difference procedure as.

\(a, b, c, d, e, .....\)

\(b - a = c - b = d - c = e - d =....\)

Step 2

For the given sequence, check whether it follows the common difference as suggested above.

\(11, 10.2, 9.4, 8.6, 7.8,....\)

\(10.2 - 11 = -0.8\)

\(9.4 - 10.2 = -0.8\)

\(8.6 - 9.4 = -0.8\)

\(7.8 - 8.6 = -0.8\)

Step 3

As it follows the common difference procedure therefore it can be concluded that the given sequence is an arithmetic sequence and common difference ‘d’ is calculated to be as.

\(d = 10.2 - 11\)

\(= -0.8\)