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Finding the Fourth Proportional to 819.31, 1,229.60 and 611.60

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Solution

The fourth proportional to 819.31, 1,229.60 and 611.60 is: 917.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.31 : 1,229.60 = 611.60 : x
  2. Step 2: Convert to fraction form
    819.31/1,229.60 = 611.60/x
  3. Step 3: Cross multiply
    819.31x = 1,229.60 × 611.60
  4. Step 4: Simplify right side
    819.31x = 752,020.29
  5. Step 5: Solve for x
    x = 752,020.29/819.31
  6. Step 6: Final answer
    x = 917.87

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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.