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Finding the Fourth Proportional to 168.60, 252.75 and 81.90

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Solution

The fourth proportional to 168.60, 252.75 and 81.90 is: 122.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    168.60 : 252.75 = 81.90 : x
  2. Step 2: Convert to fraction form
    168.60/252.75 = 81.90/x
  3. Step 3: Cross multiply
    168.60x = 252.75 × 81.90
  4. Step 4: Simplify right side
    168.60x = 20,700.23
  5. Step 5: Solve for x
    x = 20,700.23/168.60
  6. Step 6: Final answer
    x = 122.78

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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.