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Finding the Fourth Proportional to 139.97, 209.93 and 85.82

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Solution

The fourth proportional to 139.97, 209.93 and 85.82 is: 128.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.97 : 209.93 = 85.82 : x
  2. Step 2: Convert to fraction form
    139.97/209.93 = 85.82/x
  3. Step 3: Cross multiply
    139.97x = 209.93 × 85.82
  4. Step 4: Simplify right side
    139.97x = 18,015.76
  5. Step 5: Solve for x
    x = 18,015.76/139.97
  6. Step 6: Final answer
    x = 128.71

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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.