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Finding the Fourth Proportional to 87.87, 131.17 and 81.53

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Solution

The fourth proportional to 87.87, 131.17 and 81.53 is: 121.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.87 : 131.17 = 81.53 : x
  2. Step 2: Convert to fraction form
    87.87/131.17 = 81.53/x
  3. Step 3: Cross multiply
    87.87x = 131.17 × 81.53
  4. Step 4: Simplify right side
    87.87x = 10,694.29
  5. Step 5: Solve for x
    x = 10,694.29/87.87
  6. Step 6: Final answer
    x = 121.71

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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.