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Finding the Fourth Proportional to 396.45, 547.13 and 221.80

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Solution

The fourth proportional to 396.45, 547.13 and 221.80 is: 306.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    396.45 : 547.13 = 221.80 : x
  2. Step 2: Convert to fraction form
    396.45/547.13 = 221.80/x
  3. Step 3: Cross multiply
    396.45x = 547.13 × 221.80
  4. Step 4: Simplify right side
    396.45x = 121,353.43
  5. Step 5: Solve for x
    x = 121,353.43/396.45
  6. Step 6: Final answer
    x = 306.10

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.