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Finding the Fourth Proportional to 853.64, 1,280.07 and 391.31

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Solution

The fourth proportional to 853.64, 1,280.07 and 391.31 is: 586.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.64 : 1,280.07 = 391.31 : x
  2. Step 2: Convert to fraction form
    853.64/1,280.07 = 391.31/x
  3. Step 3: Cross multiply
    853.64x = 1,280.07 × 391.31
  4. Step 4: Simplify right side
    853.64x = 500,897.79
  5. Step 5: Solve for x
    x = 500,897.79/853.64
  6. Step 6: Final answer
    x = 586.78

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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.