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Finding the Fourth Proportional to 140.87, 211.08 and 86.61

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Solution

The fourth proportional to 140.87, 211.08 and 86.61 is: 129.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.87 : 211.08 = 86.61 : x
  2. Step 2: Convert to fraction form
    140.87/211.08 = 86.61/x
  3. Step 3: Cross multiply
    140.87x = 211.08 × 86.61
  4. Step 4: Simplify right side
    140.87x = 18,281.21
  5. Step 5: Solve for x
    x = 18,281.21/140.87
  6. Step 6: Final answer
    x = 129.77

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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.