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Finding the Fourth Proportional to 139.38, 209.76 and 115.20

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Solution

The fourth proportional to 139.38, 209.76 and 115.20 is: 173.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.38 : 209.76 = 115.20 : x
  2. Step 2: Convert to fraction form
    139.38/209.76 = 115.20/x
  3. Step 3: Cross multiply
    139.38x = 209.76 × 115.20
  4. Step 4: Simplify right side
    139.38x = 24,164.35
  5. Step 5: Solve for x
    x = 24,164.35/139.38
  6. Step 6: Final answer
    x = 173.37

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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.