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Finding the Fourth Proportional to 139, 208.68 and 129.49

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Solution

The fourth proportional to 139, 208.68 and 129.49 is: 194.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    139 : 208.68 = 129.49 : x
  2. Step 2: Convert to fraction form
    139/208.68 = 129.49/x
  3. Step 3: Cross multiply
    139x = 208.68 × 129.49
  4. Step 4: Simplify right side
    139x = 27,021.97
  5. Step 5: Solve for x
    x = 27,021.97/139
  6. Step 6: Final answer
    x = 194.40

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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.