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Finding the Fourth Proportional to 381.78, 572.81 and 138.38

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Solution

The fourth proportional to 381.78, 572.81 and 138.38 is: 207.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.78 : 572.81 = 138.38 : x
  2. Step 2: Convert to fraction form
    381.78/572.81 = 138.38/x
  3. Step 3: Cross multiply
    381.78x = 572.81 × 138.38
  4. Step 4: Simplify right side
    381.78x = 79,261.89
  5. Step 5: Solve for x
    x = 79,261.89/381.78
  6. Step 6: Final answer
    x = 207.61

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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.