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Finding the Fourth Proportional to 259.38, 389.13 and 86.05

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Solution

The fourth proportional to 259.38, 389.13 and 86.05 is: 129.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.38 : 389.13 = 86.05 : x
  2. Step 2: Convert to fraction form
    259.38/389.13 = 86.05/x
  3. Step 3: Cross multiply
    259.38x = 389.13 × 86.05
  4. Step 4: Simplify right side
    259.38x = 33,484.64
  5. Step 5: Solve for x
    x = 33,484.64/259.38
  6. Step 6: Final answer
    x = 129.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.