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Finding the Fourth Proportional to 87.43, 120.75 and 81.97

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Solution

The fourth proportional to 87.43, 120.75 and 81.97 is: 113.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.43 : 120.75 = 81.97 : x
  2. Step 2: Convert to fraction form
    87.43/120.75 = 81.97/x
  3. Step 3: Cross multiply
    87.43x = 120.75 × 81.97
  4. Step 4: Simplify right side
    87.43x = 9,897.88
  5. Step 5: Solve for x
    x = 9,897.88/87.43
  6. Step 6: Final answer
    x = 113.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.