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Finding the Third Proportional to 84 and 108

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Solution

The third proportional to 84 and 108 is: 138.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    84 : 108 = 108 : x
  2. Step 2: Convert to fraction form
    84/108 = 108/x
  3. Step 3: Cross multiply
    84x = 108 × 108
  4. Step 4: Simplify right side
    84x = 11,664
  5. Step 5: Solve for x
    x = 11,664/84
  6. Step 6: Final answer
    x = 138.86

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Why These Related Problems?

These problems maintain the same ratio (1.29) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.