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Finding the Fourth Proportional to 139.62, 209.46 and 42.12

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Solution

The fourth proportional to 139.62, 209.46 and 42.12 is: 63.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.62 : 209.46 = 42.12 : x
  2. Step 2: Convert to fraction form
    139.62/209.46 = 42.12/x
  3. Step 3: Cross multiply
    139.62x = 209.46 × 42.12
  4. Step 4: Simplify right side
    139.62x = 8,823.08
  5. Step 5: Solve for x
    x = 8,823.08/139.62
  6. Step 6: Final answer
    x = 63.19

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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.