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Finding the Fourth Proportional to 819.34, 1,227.38 and 386.80

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Solution

The fourth proportional to 819.34, 1,227.38 and 386.80 is: 579.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.34 : 1,227.38 = 386.80 : x
  2. Step 2: Convert to fraction form
    819.34/1,227.38 = 386.80/x
  3. Step 3: Cross multiply
    819.34x = 1,227.38 × 386.80
  4. Step 4: Simplify right side
    819.34x = 474,745.58
  5. Step 5: Solve for x
    x = 474,745.58/819.34
  6. Step 6: Final answer
    x = 579.43

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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.