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Finding the Fourth Proportional to 551.78, 826.41 and 428.30

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Solution

The fourth proportional to 551.78, 826.41 and 428.30 is: 641.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    551.78 : 826.41 = 428.30 : x
  2. Step 2: Convert to fraction form
    551.78/826.41 = 428.30/x
  3. Step 3: Cross multiply
    551.78x = 826.41 × 428.30
  4. Step 4: Simplify right side
    551.78x = 353,951.40
  5. Step 5: Solve for x
    x = 353,951.40/551.78
  6. Step 6: Final answer
    x = 641.47

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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.