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Finding the Fourth Proportional to 139.62, 209.69 and 90.92

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Solution

The fourth proportional to 139.62, 209.69 and 90.92 is: 136.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.62 : 209.69 = 90.92 : x
  2. Step 2: Convert to fraction form
    139.62/209.69 = 90.92/x
  3. Step 3: Cross multiply
    139.62x = 209.69 × 90.92
  4. Step 4: Simplify right side
    139.62x = 19,065.43
  5. Step 5: Solve for x
    x = 19,065.43/139.62
  6. Step 6: Final answer
    x = 136.55

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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.