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Finding the Fourth Proportional to 396.20, 545.10 and 385.40

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Solution

The fourth proportional to 396.20, 545.10 and 385.40 is: 530.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    396.20 : 545.10 = 385.40 : x
  2. Step 2: Convert to fraction form
    396.20/545.10 = 385.40/x
  3. Step 3: Cross multiply
    396.20x = 545.10 × 385.40
  4. Step 4: Simplify right side
    396.20x = 210,081.54
  5. Step 5: Solve for x
    x = 210,081.54/396.20
  6. Step 6: Final answer
    x = 530.24

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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.