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Finding the Fourth Proportional to 139.11, 208.86 and 136.68

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Solution

The fourth proportional to 139.11, 208.86 and 136.68 is: 205.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.11 : 208.86 = 136.68 : x
  2. Step 2: Convert to fraction form
    139.11/208.86 = 136.68/x
  3. Step 3: Cross multiply
    139.11x = 208.86 × 136.68
  4. Step 4: Simplify right side
    139.11x = 28,546.98
  5. Step 5: Solve for x
    x = 28,546.98/139.11
  6. Step 6: Final answer
    x = 205.21

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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.