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Finding the Fourth Proportional to 425.78, 638.90 and 418.15

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Solution

The fourth proportional to 425.78, 638.90 and 418.15 is: 627.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.78 : 638.90 = 418.15 : x
  2. Step 2: Convert to fraction form
    425.78/638.90 = 418.15/x
  3. Step 3: Cross multiply
    425.78x = 638.90 × 418.15
  4. Step 4: Simplify right side
    425.78x = 267,156.00
  5. Step 5: Solve for x
    x = 267,156.00/425.78
  6. Step 6: Final answer
    x = 627.45

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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.