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Finding the Fourth Proportional to 139.73, 209.49 and 81.08

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Solution

The fourth proportional to 139.73, 209.49 and 81.08 is: 121.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.73 : 209.49 = 81.08 : x
  2. Step 2: Convert to fraction form
    139.73/209.49 = 81.08/x
  3. Step 3: Cross multiply
    139.73x = 209.49 × 81.08
  4. Step 4: Simplify right side
    139.73x = 16,985.97
  5. Step 5: Solve for x
    x = 16,985.97/139.73
  6. Step 6: Final answer
    x = 121.56

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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.