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Finding the Fourth Proportional to 103.50, 155.12 and 81.86

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Solution

The fourth proportional to 103.50, 155.12 and 81.86 is: 122.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.50 : 155.12 = 81.86 : x
  2. Step 2: Convert to fraction form
    103.50/155.12 = 81.86/x
  3. Step 3: Cross multiply
    103.50x = 155.12 × 81.86
  4. Step 4: Simplify right side
    103.50x = 12,698.12
  5. Step 5: Solve for x
    x = 12,698.12/103.50
  6. Step 6: Final answer
    x = 122.69

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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.