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Finding the Fourth Proportional to 87.82, 121.18 and 71.42

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Solution

The fourth proportional to 87.82, 121.18 and 71.42 is: 98.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.82 : 121.18 = 71.42 : x
  2. Step 2: Convert to fraction form
    87.82/121.18 = 71.42/x
  3. Step 3: Cross multiply
    87.82x = 121.18 × 71.42
  4. Step 4: Simplify right side
    87.82x = 8,654.68
  5. Step 5: Solve for x
    x = 8,654.68/87.82
  6. Step 6: Final answer
    x = 98.55

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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.