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Finding the Fourth Proportional to 139.90, 209.94 and 137.68

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Solution

The fourth proportional to 139.90, 209.94 and 137.68 is: 206.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.90 : 209.94 = 137.68 : x
  2. Step 2: Convert to fraction form
    139.90/209.94 = 137.68/x
  3. Step 3: Cross multiply
    139.90x = 209.94 × 137.68
  4. Step 4: Simplify right side
    139.90x = 28,904.54
  5. Step 5: Solve for x
    x = 28,904.54/139.90
  6. Step 6: Final answer
    x = 206.61

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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.