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Finding the Fourth Proportional to 819.40, 1,229.10 and 765.40

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Solution

The fourth proportional to 819.40, 1,229.10 and 765.40 is: 1,148.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.40 : 1,229.10 = 765.40 : x
  2. Step 2: Convert to fraction form
    819.40/1,229.10 = 765.40/x
  3. Step 3: Cross multiply
    819.40x = 1,229.10 × 765.40
  4. Step 4: Simplify right side
    819.40x = 940,753.14
  5. Step 5: Solve for x
    x = 940,753.14/819.40
  6. Step 6: Final answer
    x = 1,148.10

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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.