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Finding the Fourth Proportional to 128.54, 191.85 and 111.11

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Solution

The fourth proportional to 128.54, 191.85 and 111.11 is: 165.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.54 : 191.85 = 111.11 : x
  2. Step 2: Convert to fraction form
    128.54/191.85 = 111.11/x
  3. Step 3: Cross multiply
    128.54x = 191.85 × 111.11
  4. Step 4: Simplify right side
    128.54x = 21,315.90
  5. Step 5: Solve for x
    x = 21,315.90/128.54
  6. Step 6: Final answer
    x = 165.83

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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.