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Finding the Fourth Proportional to 87.38, 121.40 and 86.27

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Solution

The fourth proportional to 87.38, 121.40 and 86.27 is: 119.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.38 : 121.40 = 86.27 : x
  2. Step 2: Convert to fraction form
    87.38/121.40 = 86.27/x
  3. Step 3: Cross multiply
    87.38x = 121.40 × 86.27
  4. Step 4: Simplify right side
    87.38x = 10,472.46
  5. Step 5: Solve for x
    x = 10,472.46/87.38
  6. Step 6: Final answer
    x = 119.85

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.