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Finding the Fourth Proportional to 81.71, 122.41 and 51.28

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Solution

The fourth proportional to 81.71, 122.41 and 51.28 is: 76.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.71 : 122.41 = 51.28 : x
  2. Step 2: Convert to fraction form
    81.71/122.41 = 51.28/x
  3. Step 3: Cross multiply
    81.71x = 122.41 × 51.28
  4. Step 4: Simplify right side
    81.71x = 6,277.63
  5. Step 5: Solve for x
    x = 6,277.63/81.71
  6. Step 6: Final answer
    x = 76.83

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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.