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Finding the Fourth Proportional to 425.88, 639.66 and 408.36

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Solution

The fourth proportional to 425.88, 639.66 and 408.36 is: 613.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.88 : 639.66 = 408.36 : x
  2. Step 2: Convert to fraction form
    425.88/639.66 = 408.36/x
  3. Step 3: Cross multiply
    425.88x = 639.66 × 408.36
  4. Step 4: Simplify right side
    425.88x = 261,211.56
  5. Step 5: Solve for x
    x = 261,211.56/425.88
  6. Step 6: Final answer
    x = 613.35

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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.