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Finding the Fourth Proportional to 102.92, 154.22 and 81.31

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Solution

The fourth proportional to 102.92, 154.22 and 81.31 is: 121.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.92 : 154.22 = 81.31 : x
  2. Step 2: Convert to fraction form
    102.92/154.22 = 81.31/x
  3. Step 3: Cross multiply
    102.92x = 154.22 × 81.31
  4. Step 4: Simplify right side
    102.92x = 12,538.86
  5. Step 5: Solve for x
    x = 12,538.86/102.92
  6. Step 6: Final answer
    x = 121.84

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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.