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Finding the Fourth Proportional to 425.90, 638.85 and 309.80

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Solution

The fourth proportional to 425.90, 638.85 and 309.80 is: 464.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.90 : 638.85 = 309.80 : x
  2. Step 2: Convert to fraction form
    425.90/638.85 = 309.80/x
  3. Step 3: Cross multiply
    425.90x = 638.85 × 309.80
  4. Step 4: Simplify right side
    425.90x = 197,915.73
  5. Step 5: Solve for x
    x = 197,915.73/425.90
  6. Step 6: Final answer
    x = 464.70

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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.