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Finding the Fourth Proportional to 128.05, 191.82 and 76.73

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Solution

The fourth proportional to 128.05, 191.82 and 76.73 is: 114.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.05 : 191.82 = 76.73 : x
  2. Step 2: Convert to fraction form
    128.05/191.82 = 76.73/x
  3. Step 3: Cross multiply
    128.05x = 191.82 × 76.73
  4. Step 4: Simplify right side
    128.05x = 14,717.87
  5. Step 5: Solve for x
    x = 14,717.87/128.05
  6. Step 6: Final answer
    x = 114.94

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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.