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Finding the Fourth Proportional to 87.27, 129.98 and 81.63

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Solution

The fourth proportional to 87.27, 129.98 and 81.63 is: 121.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.27 : 129.98 = 81.63 : x
  2. Step 2: Convert to fraction form
    87.27/129.98 = 81.63/x
  3. Step 3: Cross multiply
    87.27x = 129.98 × 81.63
  4. Step 4: Simplify right side
    87.27x = 10,609.86
  5. Step 5: Solve for x
    x = 10,609.86/87.27
  6. Step 6: Final answer
    x = 121.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.