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Finding the Fourth Proportional to 82.20, 122.31 and 81.93

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Solution

The fourth proportional to 82.20, 122.31 and 81.93 is: 121.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.20 : 122.31 = 81.93 : x
  2. Step 2: Convert to fraction form
    82.20/122.31 = 81.93/x
  3. Step 3: Cross multiply
    82.20x = 122.31 × 81.93
  4. Step 4: Simplify right side
    82.20x = 10,020.86
  5. Step 5: Solve for x
    x = 10,020.86/82.20
  6. Step 6: Final answer
    x = 121.91

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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.