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Finding the Fourth Proportional to 257.20, 385.64 and 103.15

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Solution

The fourth proportional to 257.20, 385.64 and 103.15 is: 154.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.20 : 385.64 = 103.15 : x
  2. Step 2: Convert to fraction form
    257.20/385.64 = 103.15/x
  3. Step 3: Cross multiply
    257.20x = 385.64 × 103.15
  4. Step 4: Simplify right side
    257.20x = 39,778.77
  5. Step 5: Solve for x
    x = 39,778.77/257.20
  6. Step 6: Final answer
    x = 154.66

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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.