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Finding the Fourth Proportional to 81.75, 122.72 and 51.38

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Solution

The fourth proportional to 81.75, 122.72 and 51.38 is: 77.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.75 : 122.72 = 51.38 : x
  2. Step 2: Convert to fraction form
    81.75/122.72 = 51.38/x
  3. Step 3: Cross multiply
    81.75x = 122.72 × 51.38
  4. Step 4: Simplify right side
    81.75x = 6,304.48
  5. Step 5: Solve for x
    x = 6,304.48/81.75
  6. Step 6: Final answer
    x = 77.12

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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.