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Finding the Fourth Proportional to 128.75, 191.66 and 122.85

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Solution

The fourth proportional to 128.75, 191.66 and 122.85 is: 182.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.75 : 191.66 = 122.85 : x
  2. Step 2: Convert to fraction form
    128.75/191.66 = 122.85/x
  3. Step 3: Cross multiply
    128.75x = 191.66 × 122.85
  4. Step 4: Simplify right side
    128.75x = 23,545.43
  5. Step 5: Solve for x
    x = 23,545.43/128.75
  6. Step 6: Final answer
    x = 182.88

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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.