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Finding the Fourth Proportional to 139.28, 209.10 and 112.42

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Solution

The fourth proportional to 139.28, 209.10 and 112.42 is: 168.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.28 : 209.10 = 112.42 : x
  2. Step 2: Convert to fraction form
    139.28/209.10 = 112.42/x
  3. Step 3: Cross multiply
    139.28x = 209.10 × 112.42
  4. Step 4: Simplify right side
    139.28x = 23,507.02
  5. Step 5: Solve for x
    x = 23,507.02/139.28
  6. Step 6: Final answer
    x = 168.78

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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.