Question

If the 10th term of a geometric progression is 9 and 4th term is 4, then its 7th term is

Answer 1

Step-by-step explanation:

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The terms of a  G.P. are of form  a, ar, ar2, ar3,....

ar9 = 9

So, r9 = 9/a -----(1)

ar3 = 4 ----- (2)

Cubing both sides of (2), we get,

a3r9 = 64

putting value of r9 in this, we get,

a3 X 9/a = 64

9a2 = 64

a2 = 64/9

a = 8/3

Putting value of a = 8/3 in (2)

8/3 X r3 = 4

r3 = 12/8

Now, 7th term = ar6

                        = 8/3 X (r3)2

                         = 8/3 X 144/64

                         = 6

HOPE IT HELPS YOU!!!!!

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Answer 2

Answer:

6

Step-by-step explanation:

The terms of a  G.P. are of form  a, ar, ar2, ar3,....

ar9 = 9

So, r9 = 9/a -----(1)

ar3 = 4 ----- (2)

Cubing both sides of (2), we get,

a3r9 = 64

putting value of r9 in this, we get,

a3 X 9/a = 64

9a2 = 64

a2 = 64/9

a = 8/3

Putting value of a = 8/3 in (2)

8/3 X r3 = 4

r3 = 12/8

Now, 7th term = ar6

                       = 8/3 X (r3)2

                        = 8/3 X 144/64

                      =6