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Finding the Fourth Proportional to 612.78, 845.42 and 391.83

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Solution

The fourth proportional to 612.78, 845.42 and 391.83 is: 540.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.78 : 845.42 = 391.83 : x
  2. Step 2: Convert to fraction form
    612.78/845.42 = 391.83/x
  3. Step 3: Cross multiply
    612.78x = 845.42 × 391.83
  4. Step 4: Simplify right side
    612.78x = 331,258.96
  5. Step 5: Solve for x
    x = 331,258.96/612.78
  6. Step 6: Final answer
    x = 540.58

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.