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Finding the Fourth Proportional to 159.60, 239.31 and 86.55

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Solution

The fourth proportional to 159.60, 239.31 and 86.55 is: 129.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.60 : 239.31 = 86.55 : x
  2. Step 2: Convert to fraction form
    159.60/239.31 = 86.55/x
  3. Step 3: Cross multiply
    159.60x = 239.31 × 86.55
  4. Step 4: Simplify right side
    159.60x = 20,712.28
  5. Step 5: Solve for x
    x = 20,712.28/159.60
  6. Step 6: Final answer
    x = 129.78

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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.