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Finding the Fourth Proportional to 87.87, 131.90 and 81.49

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Solution

The fourth proportional to 87.87, 131.90 and 81.49 is: 122.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.87 : 131.90 = 81.49 : x
  2. Step 2: Convert to fraction form
    87.87/131.90 = 81.49/x
  3. Step 3: Cross multiply
    87.87x = 131.90 × 81.49
  4. Step 4: Simplify right side
    87.87x = 10,748.53
  5. Step 5: Solve for x
    x = 10,748.53/87.87
  6. Step 6: Final answer
    x = 122.32

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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.