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37 votes
37 votes
Lena is asked to write an explicit formula for the graphed geometric sequence.

On a coordinate plane, 3 points are plotted. The points are (1, 1), (2, 2.5), (3, 6.25).

What value, written as a decimal, should Lena use as the common ratio

User Amin Fazlali
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3.5k points

2 Answers

22 votes
22 votes

Answer: 2.5 or "C"

Step-by-step explanation: this is right on the edge i just did the test.....Hope this helps :D

User Jeremiah Smith
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3.2k points
13 votes
13 votes

Answer:

Common Ratio = 2.5

Step-by-step explanation:

Given

Points: (1, 1), (2, 2.5), (3, 6.25)

Required

Determine the common ratio

The points can be rewritten as:

x --- f(x)

1 ---- 1

2 --- 2.5

3 ---- 6.25

The data under the x column are the domain of the function and in this case, they are not needed;

To calculate common ration, Lena should use data in function f(x) column

Common ratio is calculated by dividing a term by the previous term;

Hence;

Common Ratio = 2.5/1 or 6.25/2.5

Common Ratio = 2.5 or 2.5

Notice that, the results are the same;

Hence, the usable common ratio is 2.5

User Kris Kilton
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2.3k points