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Finding the Fourth Proportional to 139.59, 208.31 and 129.40

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Solution

The fourth proportional to 139.59, 208.31 and 129.40 is: 193.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.59 : 208.31 = 129.40 : x
  2. Step 2: Convert to fraction form
    139.59/208.31 = 129.40/x
  3. Step 3: Cross multiply
    139.59x = 208.31 × 129.40
  4. Step 4: Simplify right side
    139.59x = 26,954.15
  5. Step 5: Solve for x
    x = 26,954.15/139.59
  6. Step 6: Final answer
    x = 193.10

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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.