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Finding the Fourth Proportional to 91.89, 137.17 and 85.57

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Solution

The fourth proportional to 91.89, 137.17 and 85.57 is: 127.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.89 : 137.17 = 85.57 : x
  2. Step 2: Convert to fraction form
    91.89/137.17 = 85.57/x
  3. Step 3: Cross multiply
    91.89x = 137.17 × 85.57
  4. Step 4: Simplify right side
    91.89x = 11,737.64
  5. Step 5: Solve for x
    x = 11,737.64/91.89
  6. Step 6: Final answer
    x = 127.74

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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.