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Finding the Fourth Proportional to 91.05, 135.96 and 85.61

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Solution

The fourth proportional to 91.05, 135.96 and 85.61 is: 127.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.05 : 135.96 = 85.61 : x
  2. Step 2: Convert to fraction form
    91.05/135.96 = 85.61/x
  3. Step 3: Cross multiply
    91.05x = 135.96 × 85.61
  4. Step 4: Simplify right side
    91.05x = 11,638.86
  5. Step 5: Solve for x
    x = 11,638.86/91.05
  6. Step 6: Final answer
    x = 127.83

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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.