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Finding the Fourth Proportional to 139.88, 208.68 and 129.40

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Solution

The fourth proportional to 139.88, 208.68 and 129.40 is: 193.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.88 : 208.68 = 129.40 : x
  2. Step 2: Convert to fraction form
    139.88/208.68 = 129.40/x
  3. Step 3: Cross multiply
    139.88x = 208.68 × 129.40
  4. Step 4: Simplify right side
    139.88x = 27,002.19
  5. Step 5: Solve for x
    x = 27,002.19/139.88
  6. Step 6: Final answer
    x = 193.04

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.