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Finding the Fourth Proportional to 429.20, 642.89 and 418.87

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Solution

The fourth proportional to 429.20, 642.89 and 418.87 is: 627.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.20 : 642.89 = 418.87 : x
  2. Step 2: Convert to fraction form
    429.20/642.89 = 418.87/x
  3. Step 3: Cross multiply
    429.20x = 642.89 × 418.87
  4. Step 4: Simplify right side
    429.20x = 269,286.83
  5. Step 5: Solve for x
    x = 269,286.83/429.20
  6. Step 6: Final answer
    x = 627.42

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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.