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Finding the Fourth Proportional to 938.60, 1,408.20 and 418.40

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Solution

The fourth proportional to 938.60, 1,408.20 and 418.40 is: 627.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.60 : 1,408.20 = 418.40 : x
  2. Step 2: Convert to fraction form
    938.60/1,408.20 = 418.40/x
  3. Step 3: Cross multiply
    938.60x = 1,408.20 × 418.40
  4. Step 4: Simplify right side
    938.60x = 589,190.88
  5. Step 5: Solve for x
    x = 589,190.88/938.60
  6. Step 6: Final answer
    x = 627.73

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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.