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Finding the Fourth Proportional to 87.60, 132.18 and 81.12

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Solution

The fourth proportional to 87.60, 132.18 and 81.12 is: 122.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.60 : 132.18 = 81.12 : x
  2. Step 2: Convert to fraction form
    87.60/132.18 = 81.12/x
  3. Step 3: Cross multiply
    87.60x = 132.18 × 81.12
  4. Step 4: Simplify right side
    87.60x = 10,722.44
  5. Step 5: Solve for x
    x = 10,722.44/87.60
  6. Step 6: Final answer
    x = 122.40

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.