the 2nd term in a geometric sequence is 20 the 4th term in the same sequence is 45/4 or 11.25 what is the common ratio?

2 answers:

5 0

Let x be the common ratio and y be the 3rd term

11.25/x=y This means the fourth term divided by the common ratio will get the third term
20x=y This means the second term multiplied by the common ratio will get the third term

11.25/x=20x Set the two y's equal to each other, and solve for x!
20x^2=11.25
x^2=.5625
x=+-√.5625
x=.75 or -.75

navik [9.2K]3 years ago

3 0

__ , 20, __, 11.25

11.25 = 20 * r^(3-1)
11.25/20 = r^2
0.5625 = r^2
sqrt 0.5625 = r
0.75 = r...so common difference is 0.75 or 3/4

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Answer:

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Step-by-step explanation:

Given:

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Let the length of actual train's car be $x.$