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Finding the Fourth Proportional to 81.49, 122.12 and 61.19

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Solution

The fourth proportional to 81.49, 122.12 and 61.19 is: 91.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.49 : 122.12 = 61.19 : x
  2. Step 2: Convert to fraction form
    81.49/122.12 = 61.19/x
  3. Step 3: Cross multiply
    81.49x = 122.12 × 61.19
  4. Step 4: Simplify right side
    81.49x = 7,472.52
  5. Step 5: Solve for x
    x = 7,472.52/81.49
  6. Step 6: Final answer
    x = 91.70

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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.