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Finding the Fourth Proportional to 139.17, 209.21 and 129.15

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Solution

The fourth proportional to 139.17, 209.21 and 129.15 is: 194.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.17 : 209.21 = 129.15 : x
  2. Step 2: Convert to fraction form
    139.17/209.21 = 129.15/x
  3. Step 3: Cross multiply
    139.17x = 209.21 × 129.15
  4. Step 4: Simplify right side
    139.17x = 27,018.83
  5. Step 5: Solve for x
    x = 27,018.83/139.17
  6. Step 6: Final answer
    x = 194.14

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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.