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Finding the Fourth Proportional to 819.69, 1,229.07 and 381.38

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Solution

The fourth proportional to 819.69, 1,229.07 and 381.38 is: 571.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.69 : 1,229.07 = 381.38 : x
  2. Step 2: Convert to fraction form
    819.69/1,229.07 = 381.38/x
  3. Step 3: Cross multiply
    819.69x = 1,229.07 × 381.38
  4. Step 4: Simplify right side
    819.69x = 468,734.66
  5. Step 5: Solve for x
    x = 468,734.66/819.69
  6. Step 6: Final answer
    x = 571.85

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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.