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Finding the Fourth Proportional to 426.38, 639.64 and 137.88

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Solution

The fourth proportional to 426.38, 639.64 and 137.88 is: 206.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.38 : 639.64 = 137.88 : x
  2. Step 2: Convert to fraction form
    426.38/639.64 = 137.88/x
  3. Step 3: Cross multiply
    426.38x = 639.64 × 137.88
  4. Step 4: Simplify right side
    426.38x = 88,193.56
  5. Step 5: Solve for x
    x = 88,193.56/426.38
  6. Step 6: Final answer
    x = 206.84

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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.