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Finding the Fourth Proportional to 819.68, 1,230.72 and 387.68

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Solution

The fourth proportional to 819.68, 1,230.72 and 387.68 is: 582.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.68 : 1,230.72 = 387.68 : x
  2. Step 2: Convert to fraction form
    819.68/1,230.72 = 387.68/x
  3. Step 3: Cross multiply
    819.68x = 1,230.72 × 387.68
  4. Step 4: Simplify right side
    819.68x = 477,125.53
  5. Step 5: Solve for x
    x = 477,125.53/819.68
  6. Step 6: Final answer
    x = 582.09

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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.