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Finding the Third Proportional to 81 and 89

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Solution

The third proportional to 81 and 89 is: 97.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    81 : 89 = 89 : x
  2. Step 2: Convert to fraction form
    81/89 = 89/x
  3. Step 3: Cross multiply
    81x = 89 × 89
  4. Step 4: Simplify right side
    81x = 7,921
  5. Step 5: Solve for x
    x = 7,921/81
  6. Step 6: Final answer
    x = 97.79

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Why These Related Problems?

These problems maintain the same ratio (1.10) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.