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Finding the Fourth Proportional to 82.17, 122.26 and 81.90

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Solution

The fourth proportional to 82.17, 122.26 and 81.90 is: 121.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.17 : 122.26 = 81.90 : x
  2. Step 2: Convert to fraction form
    82.17/122.26 = 81.90/x
  3. Step 3: Cross multiply
    82.17x = 122.26 × 81.90
  4. Step 4: Simplify right side
    82.17x = 10,013.09
  5. Step 5: Solve for x
    x = 10,013.09/82.17
  6. Step 6: Final answer
    x = 121.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.