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Finding the Fourth Proportional to 128.13, 175.86 and 122.85

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Solution

The fourth proportional to 128.13, 175.86 and 122.85 is: 168.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.13 : 175.86 = 122.85 : x
  2. Step 2: Convert to fraction form
    128.13/175.86 = 122.85/x
  3. Step 3: Cross multiply
    128.13x = 175.86 × 122.85
  4. Step 4: Simplify right side
    128.13x = 21,604.40
  5. Step 5: Solve for x
    x = 21,604.40/128.13
  6. Step 6: Final answer
    x = 168.61

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.