Posted by SHERYL on .
Is there a common ratio for the geometric sequence and what are the missing terms?
16,40,100,?,?
IS there a common ratio for the geometric sequence and what are the missing terms?
81,54,?,?,?

math 
drwls,
Yes, and 2.5 is the ratio. Following terms are 150, and 225.
For the second question, try 2/3 for the ratio. 36, 24, ...
With only two terms, one really can't say if there is a "common" ratio. There are no other pairs to compare. 
math 
Jai,
if the given sequence is a geometric sequence, then it follows the formula
A,n+1 = r*(A,n)
where
r = ratio between two consecutive terms
A,n = the nth term
A,n+1 = the term after A,n
substituting the first and second term,
40 = r*16
r = 40/16
r = 2.5
to check, let's see if we would obtain 100 if we multiply 40 by the ratio=2.5
40*2.5 = 100
to find the next term after 100, we just multiply by the ratio,, thus the next two terms are:
100*2.5 = 250
250*2.5 = 625
for the second question, if it's a geometric sequence, then it follows the formula above. thus, getting the ratio,
54 = r*81
r = 54/81
r = 2/3
to get the next three terms, we multiply the next terms by 2/3:
54*(2/3) = 36
36*(2/3) = 24
24*(2/3) = 16
hope this helps~ :)