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Finding the Fourth Proportional to 819.09, 1,228.87 and 408.12

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Solution

The fourth proportional to 819.09, 1,228.87 and 408.12 is: 612.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.09 : 1,228.87 = 408.12 : x
  2. Step 2: Convert to fraction form
    819.09/1,228.87 = 408.12/x
  3. Step 3: Cross multiply
    819.09x = 1,228.87 × 408.12
  4. Step 4: Simplify right side
    819.09x = 501,526.42
  5. Step 5: Solve for x
    x = 501,526.42/819.09
  6. Step 6: Final answer
    x = 612.30

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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.