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Finding the Fourth Proportional to 128.83, 193.33 and 76.89

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Solution

The fourth proportional to 128.83, 193.33 and 76.89 is: 115.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.83 : 193.33 = 76.89 : x
  2. Step 2: Convert to fraction form
    128.83/193.33 = 76.89/x
  3. Step 3: Cross multiply
    128.83x = 193.33 × 76.89
  4. Step 4: Simplify right side
    128.83x = 14,864.18
  5. Step 5: Solve for x
    x = 14,864.18/128.83
  6. Step 6: Final answer
    x = 115.38

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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.