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Finding the Fourth Proportional to 87.62, 131.30 and 81.85

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Solution

The fourth proportional to 87.62, 131.30 and 81.85 is: 122.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.62 : 131.30 = 81.85 : x
  2. Step 2: Convert to fraction form
    87.62/131.30 = 81.85/x
  3. Step 3: Cross multiply
    87.62x = 131.30 × 81.85
  4. Step 4: Simplify right side
    87.62x = 10,746.91
  5. Step 5: Solve for x
    x = 10,746.91/87.62
  6. Step 6: Final answer
    x = 122.65

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.