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Finding the Fourth Proportional to 128.87, 193.39 and 51.85

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Solution

The fourth proportional to 128.87, 193.39 and 51.85 is: 77.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.87 : 193.39 = 51.85 : x
  2. Step 2: Convert to fraction form
    128.87/193.39 = 51.85/x
  3. Step 3: Cross multiply
    128.87x = 193.39 × 51.85
  4. Step 4: Simplify right side
    128.87x = 10,027.27
  5. Step 5: Solve for x
    x = 10,027.27/128.87
  6. Step 6: Final answer
    x = 77.81

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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.