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Finding the Fourth Proportional to 87.86, 121.17 and 61.61

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Solution

The fourth proportional to 87.86, 121.17 and 61.61 is: 84.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.86 : 121.17 = 61.61 : x
  2. Step 2: Convert to fraction form
    87.86/121.17 = 61.61/x
  3. Step 3: Cross multiply
    87.86x = 121.17 × 61.61
  4. Step 4: Simplify right side
    87.86x = 7,465.42
  5. Step 5: Solve for x
    x = 7,465.42/87.86
  6. Step 6: Final answer
    x = 84.97

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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.