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Finding the Fourth Proportional to 87.61, 131.65 and 85.11

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Solution

The fourth proportional to 87.61, 131.65 and 85.11 is: 127.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.61 : 131.65 = 85.11 : x
  2. Step 2: Convert to fraction form
    87.61/131.65 = 85.11/x
  3. Step 3: Cross multiply
    87.61x = 131.65 × 85.11
  4. Step 4: Simplify right side
    87.61x = 11,204.73
  5. Step 5: Solve for x
    x = 11,204.73/87.61
  6. Step 6: Final answer
    x = 127.89

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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.