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Finding the Fourth Proportional to 90.60, 135.68 and 89.40

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Solution

The fourth proportional to 90.60, 135.68 and 89.40 is: 133.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.60 : 135.68 = 89.40 : x
  2. Step 2: Convert to fraction form
    90.60/135.68 = 89.40/x
  3. Step 3: Cross multiply
    90.60x = 135.68 × 89.40
  4. Step 4: Simplify right side
    90.60x = 12,129.79
  5. Step 5: Solve for x
    x = 12,129.79/90.60
  6. Step 6: Final answer
    x = 133.88

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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.