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Finding the Fourth Proportional to 819.66, 1,229.16 and 380.90

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Solution

The fourth proportional to 819.66, 1,229.16 and 380.90 is: 571.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.66 : 1,229.16 = 380.90 : x
  2. Step 2: Convert to fraction form
    819.66/1,229.16 = 380.90/x
  3. Step 3: Cross multiply
    819.66x = 1,229.16 × 380.90
  4. Step 4: Simplify right side
    819.66x = 468,187.04
  5. Step 5: Solve for x
    x = 468,187.04/819.66
  6. Step 6: Final answer
    x = 571.20

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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.