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Finding the Fourth Proportional to 87.22, 120.39 and 61.42

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Solution

The fourth proportional to 87.22, 120.39 and 61.42 is: 84.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.22 : 120.39 = 61.42 : x
  2. Step 2: Convert to fraction form
    87.22/120.39 = 61.42/x
  3. Step 3: Cross multiply
    87.22x = 120.39 × 61.42
  4. Step 4: Simplify right side
    87.22x = 7,394.35
  5. Step 5: Solve for x
    x = 7,394.35/87.22
  6. Step 6: Final answer
    x = 84.78

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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.