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Finding the Fourth Proportional to 819.90, 1,230.24 and 409.09

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Solution

The fourth proportional to 819.90, 1,230.24 and 409.09 is: 613.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.90 : 1,230.24 = 409.09 : x
  2. Step 2: Convert to fraction form
    819.90/1,230.24 = 409.09/x
  3. Step 3: Cross multiply
    819.90x = 1,230.24 × 409.09
  4. Step 4: Simplify right side
    819.90x = 503,278.88
  5. Step 5: Solve for x
    x = 503,278.88/819.90
  6. Step 6: Final answer
    x = 613.83

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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.