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Finding the Fourth Proportional to 87.11, 120.12 and 81.82

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Solution

The fourth proportional to 87.11, 120.12 and 81.82 is: 112.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.11 : 120.12 = 81.82 : x
  2. Step 2: Convert to fraction form
    87.11/120.12 = 81.82/x
  3. Step 3: Cross multiply
    87.11x = 120.12 × 81.82
  4. Step 4: Simplify right side
    87.11x = 9,827.76
  5. Step 5: Solve for x
    x = 9,827.76/87.11
  6. Step 6: Final answer
    x = 112.81

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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.