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Finding the Fourth Proportional to 82.13, 122.61 and 81.56

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Solution

The fourth proportional to 82.13, 122.61 and 81.56 is: 121.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.13 : 122.61 = 81.56 : x
  2. Step 2: Convert to fraction form
    82.13/122.61 = 81.56/x
  3. Step 3: Cross multiply
    82.13x = 122.61 × 81.56
  4. Step 4: Simplify right side
    82.13x = 9,999.46
  5. Step 5: Solve for x
    x = 9,999.46/82.13
  6. Step 6: Final answer
    x = 121.76

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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.