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Finding the Fourth Proportional to 939, 1,408.05 and 391.08

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Solution

The fourth proportional to 939, 1,408.05 and 391.08 is: 586.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    939 : 1,408.05 = 391.08 : x
  2. Step 2: Convert to fraction form
    939/1,408.05 = 391.08/x
  3. Step 3: Cross multiply
    939x = 1,408.05 × 391.08
  4. Step 4: Simplify right side
    939x = 550,660.19
  5. Step 5: Solve for x
    x = 550,660.19/939
  6. Step 6: Final answer
    x = 586.43

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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.