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Finding the Fourth Proportional to 81.62, 122.71 and 65.70

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Solution

The fourth proportional to 81.62, 122.71 and 65.70 is: 98.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.62 : 122.71 = 65.70 : x
  2. Step 2: Convert to fraction form
    81.62/122.71 = 65.70/x
  3. Step 3: Cross multiply
    81.62x = 122.71 × 65.70
  4. Step 4: Simplify right side
    81.62x = 8,062.05
  5. Step 5: Solve for x
    x = 8,062.05/81.62
  6. Step 6: Final answer
    x = 98.78

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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.