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Finding the Fourth Proportional to 122.64, 168.80 and 108.72

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Solution

The fourth proportional to 122.64, 168.80 and 108.72 is: 149.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.64 : 168.80 = 108.72 : x
  2. Step 2: Convert to fraction form
    122.64/168.80 = 108.72/x
  3. Step 3: Cross multiply
    122.64x = 168.80 × 108.72
  4. Step 4: Simplify right side
    122.64x = 18,351.94
  5. Step 5: Solve for x
    x = 18,351.94/122.64
  6. Step 6: Final answer
    x = 149.64

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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.