# Use the geometric mean to find the 7th term in a geometric sequence if the 6th term is 8 and the 8th term is 18?

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12

15

7

5

12

15

7

5

##### 1 Answer

Apr 4, 2017

#### Answer:

If the common ratio is positive, then the

If not, then it would be

#### Explanation:

In a geometric sequence of positive terms, the middle term of three consecutive terms is the geometric mean of the first and third.

Given two positive numbers

#sqrt(ab)#

In our example we find that the geometric mean of

#sqrt(8*18) = sqrt(144) = 12#

So, assuming the common ratio of the geometric sequence is positive, the

Note that the