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Finding the Fourth Proportional to 217.31, 299.85 and 122.78

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Solution

The fourth proportional to 217.31, 299.85 and 122.78 is: 169.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.31 : 299.85 = 122.78 : x
  2. Step 2: Convert to fraction form
    217.31/299.85 = 122.78/x
  3. Step 3: Cross multiply
    217.31x = 299.85 × 122.78
  4. Step 4: Simplify right side
    217.31x = 36,815.58
  5. Step 5: Solve for x
    x = 36,815.58/217.31
  6. Step 6: Final answer
    x = 169.42

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.