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Finding the Fourth Proportional to 81.89, 122.74 and 51.47

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Solution

The fourth proportional to 81.89, 122.74 and 51.47 is: 77.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.89 : 122.74 = 51.47 : x
  2. Step 2: Convert to fraction form
    81.89/122.74 = 51.47/x
  3. Step 3: Cross multiply
    81.89x = 122.74 × 51.47
  4. Step 4: Simplify right side
    81.89x = 6,316.69
  5. Step 5: Solve for x
    x = 6,316.69/81.89
  6. Step 6: Final answer
    x = 77.14

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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.