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Finding the Fourth Proportional to 298.31, 447.39 and 81.90

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Solution

The fourth proportional to 298.31, 447.39 and 81.90 is: 122.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    298.31 : 447.39 = 81.90 : x
  2. Step 2: Convert to fraction form
    298.31/447.39 = 81.90/x
  3. Step 3: Cross multiply
    298.31x = 447.39 × 81.90
  4. Step 4: Simplify right side
    298.31x = 36,641.24
  5. Step 5: Solve for x
    x = 36,641.24/298.31
  6. Step 6: Final answer
    x = 122.83

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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.