What is the sum of the arithmetic sequence 4, 11, 18 …, if there are 26 terms?

d = 11-4 = 81-11 = 7

Sn = (n/2)(2a1 + (n-1)d)
S26 = (26/2)(2*4 + 25(7)

To find the sum of an arithmetic sequence, you can use the formula:

Sn = (n/2) * (a + L)

Where Sn is the sum of the sequence, n is the number of terms, a is the first term, and L is the last term.

In this case, the first term, a, is 4 and the last term, L, can be found by using the formula for the nth term of an arithmetic sequence:

Ln = a + (n-1)d

Where Ln is the last term, n is the number of terms, a is the first term, and d is the common difference between terms.

In this case, the common difference, d, can be found by subtracting the first term from the second term:

d = 11 - 4 = 7

Now we can find the last term, L:

L = 4 + (26-1)*7 = 4 + 25*7 = 4 + 175 = 179

Finally, we can calculate the sum of the sequence:

Sn = (26/2) * (4 + 179) = 13 * 183 = 2379

Therefore, the sum of the arithmetic sequence 4, 11, 18 ..., with 26 terms is 2379.