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Finding the Fourth Proportional to 87.62, 120.69 and 81.95

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Solution

The fourth proportional to 87.62, 120.69 and 81.95 is: 112.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.62 : 120.69 = 81.95 : x
  2. Step 2: Convert to fraction form
    87.62/120.69 = 81.95/x
  3. Step 3: Cross multiply
    87.62x = 120.69 × 81.95
  4. Step 4: Simplify right side
    87.62x = 9,889.94
  5. Step 5: Solve for x
    x = 9,889.94/87.62
  6. Step 6: Final answer
    x = 112.88

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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.