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Finding the Fourth Proportional to 82.18, 122.70 and 81.36

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Solution

The fourth proportional to 82.18, 122.70 and 81.36 is: 121.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.18 : 122.70 = 81.36 : x
  2. Step 2: Convert to fraction form
    82.18/122.70 = 81.36/x
  3. Step 3: Cross multiply
    82.18x = 122.70 × 81.36
  4. Step 4: Simplify right side
    82.18x = 9,983.06
  5. Step 5: Solve for x
    x = 9,983.06/82.18
  6. Step 6: Final answer
    x = 121.48

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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.