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Finding the Fourth Proportional to 139.73, 209.28 and 85.35

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Solution

The fourth proportional to 139.73, 209.28 and 85.35 is: 127.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.73 : 209.28 = 85.35 : x
  2. Step 2: Convert to fraction form
    139.73/209.28 = 85.35/x
  3. Step 3: Cross multiply
    139.73x = 209.28 × 85.35
  4. Step 4: Simplify right side
    139.73x = 17,863.15
  5. Step 5: Solve for x
    x = 17,863.15/139.73
  6. Step 6: Final answer
    x = 127.85

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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.