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Finding the Fourth Proportional to 91.91, 137.15 and 85.25

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Solution

The fourth proportional to 91.91, 137.15 and 85.25 is: 127.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.91 : 137.15 = 85.25 : x
  2. Step 2: Convert to fraction form
    91.91/137.15 = 85.25/x
  3. Step 3: Cross multiply
    91.91x = 137.15 × 85.25
  4. Step 4: Simplify right side
    91.91x = 11,690.93
  5. Step 5: Solve for x
    x = 11,690.93/91.91
  6. Step 6: Final answer
    x = 127.21

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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.