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Finding the Fourth Proportional to 819.59, 1,229.87 and 429.89

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Solution

The fourth proportional to 819.59, 1,229.87 and 429.89 is: 645.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.59 : 1,229.87 = 429.89 : x
  2. Step 2: Convert to fraction form
    819.59/1,229.87 = 429.89/x
  3. Step 3: Cross multiply
    819.59x = 1,229.87 × 429.89
  4. Step 4: Simplify right side
    819.59x = 528,703.74
  5. Step 5: Solve for x
    x = 528,703.74/819.59
  6. Step 6: Final answer
    x = 645.09

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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.