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Finding the Fourth Proportional to 426.28, 639.22 and 137.72

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Solution

The fourth proportional to 426.28, 639.22 and 137.72 is: 206.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.28 : 639.22 = 137.72 : x
  2. Step 2: Convert to fraction form
    426.28/639.22 = 137.72/x
  3. Step 3: Cross multiply
    426.28x = 639.22 × 137.72
  4. Step 4: Simplify right side
    426.28x = 88,033.38
  5. Step 5: Solve for x
    x = 88,033.38/426.28
  6. Step 6: Final answer
    x = 206.52

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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.