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Finding the Fourth Proportional to 853.86, 1,280.13 and 391.30

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Solution

The fourth proportional to 853.86, 1,280.13 and 391.30 is: 586.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.86 : 1,280.13 = 391.30 : x
  2. Step 2: Convert to fraction form
    853.86/1,280.13 = 391.30/x
  3. Step 3: Cross multiply
    853.86x = 1,280.13 × 391.30
  4. Step 4: Simplify right side
    853.86x = 500,915.00
  5. Step 5: Solve for x
    x = 500,915.00/853.86
  6. Step 6: Final answer
    x = 586.65

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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.