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Finding the Third Proportional to 81.75 and 84

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Solution

The third proportional to 81.75 and 84 is: 86.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.75 : 84 = 84 : x
  2. Step 2: Convert to fraction form
    81.75/84 = 84/x
  3. Step 3: Cross multiply
    81.75x = 84 × 84
  4. Step 4: Simplify right side
    81.75x = 7,056
  5. Step 5: Solve for x
    x = 7,056/81.75
  6. Step 6: Final answer
    x = 86.31

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Why These Related Problems?

These problems maintain the same ratio (1.03) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.