Question

What is the 9th term of the geometric sequence 4, 12, 36, ?

This is what I have so far:
tn = t1 x r ^(n-1)

t1 (1st term) = 9
n = # of terms so n = 4
9=4(1) x ratio

How would I find the ratio?

Answer 1

all you do is mulitply each number by 3 4*3=12*3=36

Answer 2

multiply*

Answer 3

that's not what the formula says

Answer 4

4, 12, 36
whats the 1st term you see ???
its not 9.

Answer 5

yeah your formula is wrong

Answer 6

How is 9 not the first term? What is?

Answer 7

oh.... 41???

Answer 8

4

Answer 9

4*?

Answer 10

your first term is always the first of the sequence that is ... 4

Answer 11

you are trying to find the 9th term

Answer 12

you want 9th term, so n=9
got this ?

Answer 13

That's what I used!!!

Answer 14

wait wait wait

Answer 15

ok

Answer 16

now common ratio , r
how do you find it ?

Answer 17

everyone's saying different things so it's rather confusing

Answer 18

a2/a1? to find the ratio?

Answer 19

yes, so, r=... ?

Answer 20

common ratio , d = 2nd term divide by 1st term

Answer 21

r*

Answer 22

a1 = 4?

Answer 23

yes.

Answer 24

12/4?

Answer 25

= 3

Answer 26

yes, r=3 is correct.

Answer 27

really? do i do that for every problem?

Answer 28

yes,
tn = t1 x r ^(n-1)

t1 (1st term) = 4
n = # of terms so n = 9
r= 3

Answer 29

ok perfect thanks:) i'll plug in the numbers now

Answer 30

Just Remember always : For a geometric progression .
The ratio between any two successive terms is called the common ratio.
The first term a1 is the first of the sequence

Answer 31

429981696

Answer 32

nooo......
how ?

Answer 33

12^(9-1)

Answer 34

4(1) x 3 = 12

Answer 35

nah...
you don't do 4*3 first

Answer 36

4 * (3^8 )
first do 3^8 then multiply by 4