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Finding the Fourth Proportional to 90.66, 135.32 and 81.54

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Solution

The fourth proportional to 90.66, 135.32 and 81.54 is: 121.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.66 : 135.32 = 81.54 : x
  2. Step 2: Convert to fraction form
    90.66/135.32 = 81.54/x
  3. Step 3: Cross multiply
    90.66x = 135.32 × 81.54
  4. Step 4: Simplify right side
    90.66x = 11,033.59
  5. Step 5: Solve for x
    x = 11,033.59/90.66
  6. Step 6: Final answer
    x = 121.70

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.