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Finding the Fourth Proportional to 819.56, 1,227.41 and 428.63

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Solution

The fourth proportional to 819.56, 1,227.41 and 428.63 is: 641.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.56 : 1,227.41 = 428.63 : x
  2. Step 2: Convert to fraction form
    819.56/1,227.41 = 428.63/x
  3. Step 3: Cross multiply
    819.56x = 1,227.41 × 428.63
  4. Step 4: Simplify right side
    819.56x = 526,108.89
  5. Step 5: Solve for x
    x = 526,108.89/819.56
  6. Step 6: Final answer
    x = 641.94

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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.