Math Problem Statement

4 geometric means between 3 and 48

Solution

To find 4 geometric means between 3 and 48, we are looking to construct a geometric sequence where 3 is the first term, 48 is the last term, and there are 4 terms in between them. Let's denote the sequence as:

3,a1,a2,a3,a4,483, \, a_1, \, a_2, \, a_3, \, a_4, \, 48

Step 1: Understanding the Geometric Sequence

In a geometric sequence, each term is obtained by multiplying the previous term by a common ratio rr. Thus, we can write:

a1=3r,a2=3r2,a3=3r3,a4=3r4,48=3r5a_1 = 3r, \quad a_2 = 3r^2, \quad a_3 = 3r^3, \quad a_4 = 3r^4, \quad 48 = 3r^5

Step 2: Solving for the Common Ratio rr

To find rr, we use the last term:

3r5=483r^5 = 48

Dividing both sides by 3:

r5=16r^5 = 16

Now, take the fifth root of both sides:

r=161/5r = 16^{1/5}

Step 3: Calculating the Common Ratio

Calculating 161/516^{1/5}:

r=2r = 2

Step 4: Finding the Geometric Means

Now that we have r=2r = 2, we can find the 4 geometric means:

a1=3r=3×2=6a_1 = 3r = 3 \times 2 = 6 a2=3r2=3×4=12a_2 = 3r^2 = 3 \times 4 = 12 a3=3r3=3×8=24a_3 = 3r^3 = 3 \times 8 = 24 a4=3r4=3×16=48a_4 = 3r^4 = 3 \times 16 = 48

Conclusion

The 4 geometric means between 3 and 48 are:

6,12,24,486, \, 12, \, 24, \, 48

Would you like more details or have any questions? Here are 5 related questions for further exploration:

  1. How do you find geometric means in a different range, such as between 5 and 125?
  2. What is the formula for finding the nn-th term of a geometric sequence?
  3. How does arithmetic progression differ from geometric progression?
  4. How can we determine the sum of a geometric series?
  5. What are the applications of geometric sequences in real-world scenarios?

Tip: When working with geometric sequences, always check if the terms grow by a constant ratio, confirming that the sequence is geometric.

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Math Problem Analysis

Mathematical Concepts

Geometric Sequence
Geometric Mean

Formulas

Geometric Mean Formula: a_n = ar^(n-1)
Common Ratio: r = (last term / first term)^(1/(n-1))

Theorems

Geometric Sequence Theorem

Suitable Grade Level

Grades 9-10