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Finding the Fourth Proportional to 81.43, 122.29 and 72.49

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Solution

The fourth proportional to 81.43, 122.29 and 72.49 is: 108.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.43 : 122.29 = 72.49 : x
  2. Step 2: Convert to fraction form
    81.43/122.29 = 72.49/x
  3. Step 3: Cross multiply
    81.43x = 122.29 × 72.49
  4. Step 4: Simplify right side
    81.43x = 8,864.80
  5. Step 5: Solve for x
    x = 8,864.80/81.43
  6. Step 6: Final answer
    x = 108.86

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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.