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Finding the Fourth Proportional to 81.85, 122.87 and 51.55

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Solution

The fourth proportional to 81.85, 122.87 and 51.55 is: 77.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.85 : 122.87 = 51.55 : x
  2. Step 2: Convert to fraction form
    81.85/122.87 = 51.55/x
  3. Step 3: Cross multiply
    81.85x = 122.87 × 51.55
  4. Step 4: Simplify right side
    81.85x = 6,333.95
  5. Step 5: Solve for x
    x = 6,333.95/81.85
  6. Step 6: Final answer
    x = 77.38

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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.