Subject: geometric sequence

Name: Wanda

Who is asking: Parent
Level: Middle

the fifth term of a geometric sequence is 5/16. the common ratio is 1/2. What are the first four terms of the sequence. I am a parent helping my child. thank you

Hi Wanda,

A geometric sequence has the form

a, ar, ar 2, ar 3, ar 4, ar 5, ar 6,... where the first term is a and the common ratio is r.

If you look at the sequence above you see that the fifth term is ar 4, and hence

ar 45/16.

You also know that r =  1/2 and hence r 4 = 1/16. Thus

ar 4a/16 = 5/16 Thus a = 5.


Go to Math Central

To return to the previous page use your browser's back button.