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Finding the Fourth Proportional to 819.54, 1,229.31 and 429.21

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Solution

The fourth proportional to 819.54, 1,229.31 and 429.21 is: 643.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.54 : 1,229.31 = 429.21 : x
  2. Step 2: Convert to fraction form
    819.54/1,229.31 = 429.21/x
  3. Step 3: Cross multiply
    819.54x = 1,229.31 × 429.21
  4. Step 4: Simplify right side
    819.54x = 527,632.15
  5. Step 5: Solve for x
    x = 527,632.15/819.54
  6. Step 6: Final answer
    x = 643.82

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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.