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Finding the Fourth Proportional to 389.78, 584.78 and 115.88

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Solution

The fourth proportional to 389.78, 584.78 and 115.88 is: 173.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.78 : 584.78 = 115.88 : x
  2. Step 2: Convert to fraction form
    389.78/584.78 = 115.88/x
  3. Step 3: Cross multiply
    389.78x = 584.78 × 115.88
  4. Step 4: Simplify right side
    389.78x = 67,765.84
  5. Step 5: Solve for x
    x = 67,765.84/389.78
  6. Step 6: Final answer
    x = 173.86

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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.