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Finding the Fourth Proportional to 391.97, 583.78 and 381.21

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Solution

The fourth proportional to 391.97, 583.78 and 381.21 is: 567.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.97 : 583.78 = 381.21 : x
  2. Step 2: Convert to fraction form
    391.97/583.78 = 381.21/x
  3. Step 3: Cross multiply
    391.97x = 583.78 × 381.21
  4. Step 4: Simplify right side
    391.97x = 222,542.77
  5. Step 5: Solve for x
    x = 222,542.77/391.97
  6. Step 6: Final answer
    x = 567.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.