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Finding the Fourth Proportional to 140.72, 210.98 and 86.60

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Solution

The fourth proportional to 140.72, 210.98 and 86.60 is: 129.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.72 : 210.98 = 86.60 : x
  2. Step 2: Convert to fraction form
    140.72/210.98 = 86.60/x
  3. Step 3: Cross multiply
    140.72x = 210.98 × 86.60
  4. Step 4: Simplify right side
    140.72x = 18,270.87
  5. Step 5: Solve for x
    x = 18,270.87/140.72
  6. Step 6: Final answer
    x = 129.84

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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.