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Finding the Fourth Proportional to 389.78, 584.69 and 129.77

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Solution

The fourth proportional to 389.78, 584.69 and 129.77 is: 194.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.78 : 584.69 = 129.77 : x
  2. Step 2: Convert to fraction form
    389.78/584.69 = 129.77/x
  3. Step 3: Cross multiply
    389.78x = 584.69 × 129.77
  4. Step 4: Simplify right side
    389.78x = 75,874.94
  5. Step 5: Solve for x
    x = 75,874.94/389.78
  6. Step 6: Final answer
    x = 194.66

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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.