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Finding the Fourth Proportional to 81.96, 123.08 and 81.33

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Solution

The fourth proportional to 81.96, 123.08 and 81.33 is: 122.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.96 : 123.08 = 81.33 : x
  2. Step 2: Convert to fraction form
    81.96/123.08 = 81.33/x
  3. Step 3: Cross multiply
    81.96x = 123.08 × 81.33
  4. Step 4: Simplify right side
    81.96x = 10,009.69
  5. Step 5: Solve for x
    x = 10,009.69/81.96
  6. Step 6: Final answer
    x = 122.13

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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.