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Finding the Fourth Proportional to 129.54, 192.81 and 128.85

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Solution

The fourth proportional to 129.54, 192.81 and 128.85 is: 191.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.54 : 192.81 = 128.85 : x
  2. Step 2: Convert to fraction form
    129.54/192.81 = 128.85/x
  3. Step 3: Cross multiply
    129.54x = 192.81 × 128.85
  4. Step 4: Simplify right side
    129.54x = 24,843.57
  5. Step 5: Solve for x
    x = 24,843.57/129.54
  6. Step 6: Final answer
    x = 191.78

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.