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Finding the Fourth Proportional to 81.89, 112.91 and 61.13

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Solution

The fourth proportional to 81.89, 112.91 and 61.13 is: 84.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.89 : 112.91 = 61.13 : x
  2. Step 2: Convert to fraction form
    81.89/112.91 = 61.13/x
  3. Step 3: Cross multiply
    81.89x = 112.91 × 61.13
  4. Step 4: Simplify right side
    81.89x = 6,902.62
  5. Step 5: Solve for x
    x = 6,902.62/81.89
  6. Step 6: Final answer
    x = 84.30

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.