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Finding the Fourth Proportional to 426.31, 639.50 and 137.76

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Solution

The fourth proportional to 426.31, 639.50 and 137.76 is: 206.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.31 : 639.50 = 137.76 : x
  2. Step 2: Convert to fraction form
    426.31/639.50 = 137.76/x
  3. Step 3: Cross multiply
    426.31x = 639.50 × 137.76
  4. Step 4: Simplify right side
    426.31x = 88,097.52
  5. Step 5: Solve for x
    x = 88,097.52/426.31
  6. Step 6: Final answer
    x = 206.65

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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.