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Finding the Fourth Proportional to 140.61, 210.81 and 86.39

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Solution

The fourth proportional to 140.61, 210.81 and 86.39 is: 129.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.61 : 210.81 = 86.39 : x
  2. Step 2: Convert to fraction form
    140.61/210.81 = 86.39/x
  3. Step 3: Cross multiply
    140.61x = 210.81 × 86.39
  4. Step 4: Simplify right side
    140.61x = 18,212.73
  5. Step 5: Solve for x
    x = 18,212.73/140.61
  6. Step 6: Final answer
    x = 129.53

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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.