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Finding the Fourth Proportional to 122.42, 168.86 and 78.14

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Solution

The fourth proportional to 122.42, 168.86 and 78.14 is: 107.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.42 : 168.86 = 78.14 : x
  2. Step 2: Convert to fraction form
    122.42/168.86 = 78.14/x
  3. Step 3: Cross multiply
    122.42x = 168.86 × 78.14
  4. Step 4: Simplify right side
    122.42x = 13,193.49
  5. Step 5: Solve for x
    x = 13,193.49/122.42
  6. Step 6: Final answer
    x = 107.78

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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.