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Finding the Fourth Proportional to 81.86, 123.28 and 61.71

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Solution

The fourth proportional to 81.86, 123.28 and 61.71 is: 92.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.86 : 123.28 = 61.71 : x
  2. Step 2: Convert to fraction form
    81.86/123.28 = 61.71/x
  3. Step 3: Cross multiply
    81.86x = 123.28 × 61.71
  4. Step 4: Simplify right side
    81.86x = 7,608.12
  5. Step 5: Solve for x
    x = 7,608.12/81.86
  6. Step 6: Final answer
    x = 92.94

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.