Question

Look at the following sequence.

128, 320, 800, 2000, . . .

If it is a geometric sequence, choose the common ratio. If it is not a geometric sequence, choose “not geometric.

Answer 1

geometric sequence

Explanation:

If the sequence is geometric then there must be a common ratio r between consecutive terms, that is

320 ÷ 128 = 2.5

800 ÷ 320 = 2.5

2000 ÷ 800 = 2.5

Since there is a common ratio r = 2.5 between consecutive terms.

Then the sequence is geometric