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Finding the Fourth Proportional to 90.38, 135.61 and 81.61

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Solution

The fourth proportional to 90.38, 135.61 and 81.61 is: 122.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.38 : 135.61 = 81.61 : x
  2. Step 2: Convert to fraction form
    90.38/135.61 = 81.61/x
  3. Step 3: Cross multiply
    90.38x = 135.61 × 81.61
  4. Step 4: Simplify right side
    90.38x = 11,066.59
  5. Step 5: Solve for x
    x = 11,066.59/90.38
  6. Step 6: Final answer
    x = 122.44

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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.