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Finding the Fourth Proportional to 257.28, 385.90 and 141.78

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Solution

The fourth proportional to 257.28, 385.90 and 141.78 is: 212.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 385.90 = 141.78 : x
  2. Step 2: Convert to fraction form
    257.28/385.90 = 141.78/x
  3. Step 3: Cross multiply
    257.28x = 385.90 × 141.78
  4. Step 4: Simplify right side
    257.28x = 54,712.62
  5. Step 5: Solve for x
    x = 54,712.62/257.28
  6. Step 6: Final answer
    x = 212.66

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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.