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Finding the Fourth Proportional to 81.66, 122.28 and 57.18

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Solution

The fourth proportional to 81.66, 122.28 and 57.18 is: 85.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.66 : 122.28 = 57.18 : x
  2. Step 2: Convert to fraction form
    81.66/122.28 = 57.18/x
  3. Step 3: Cross multiply
    81.66x = 122.28 × 57.18
  4. Step 4: Simplify right side
    81.66x = 6,991.97
  5. Step 5: Solve for x
    x = 6,991.97/81.66
  6. Step 6: Final answer
    x = 85.62

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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.