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Finding the Fourth Proportional to 140.31, 210.11 and 86.09

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Solution

The fourth proportional to 140.31, 210.11 and 86.09 is: 128.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.31 : 210.11 = 86.09 : x
  2. Step 2: Convert to fraction form
    140.31/210.11 = 86.09/x
  3. Step 3: Cross multiply
    140.31x = 210.11 × 86.09
  4. Step 4: Simplify right side
    140.31x = 18,086.89
  5. Step 5: Solve for x
    x = 18,086.89/140.31
  6. Step 6: Final answer
    x = 128.91

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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.