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Finding the Fourth Proportional to 122.12, 168.45 and 77.86

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Solution

The fourth proportional to 122.12, 168.45 and 77.86 is: 107.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.12 : 168.45 = 77.86 : x
  2. Step 2: Convert to fraction form
    122.12/168.45 = 77.86/x
  3. Step 3: Cross multiply
    122.12x = 168.45 × 77.86
  4. Step 4: Simplify right side
    122.12x = 13,115.52
  5. Step 5: Solve for x
    x = 13,115.52/122.12
  6. Step 6: Final answer
    x = 107.40

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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.