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Finding the Fourth Proportional to 629.80, 869.31 and 408.78

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Solution

The fourth proportional to 629.80, 869.31 and 408.78 is: 564.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    629.80 : 869.31 = 408.78 : x
  2. Step 2: Convert to fraction form
    629.80/869.31 = 408.78/x
  3. Step 3: Cross multiply
    629.80x = 869.31 × 408.78
  4. Step 4: Simplify right side
    629.80x = 355,356.54
  5. Step 5: Solve for x
    x = 355,356.54/629.80
  6. Step 6: Final answer
    x = 564.24

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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.