Question

The eighth term in a geometric sequence is 729. The first term in the sequence is 1/3. What is the fifth term? Please help and show work! I have no idea how to do this

Answer 1

Do we multiply by 3?

1/3 3 0 27 81 243 729
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fifth term

Answer 2

fist term = 1/3

Answer 3

eight term is 729

Answer 4

we know formula for GP
tn = ar^(n-1)

Answer 5

t1 = 1/3

Answer 6

t8 = 729

Answer 7

t8/t1 = ar^7/a = 729/(1/3)

Answer 8

cancel out 'a'

Answer 9

r^7 = 729/(1/3)

Answer 10

r^7 = 729*3

Answer 11

r^7 = 2187

Answer 12

Answer is t5 = 27

Answer 13

Can you explain how you set up the formula please?