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Finding the Fourth Proportional to 426.38, 639.56 and 137.81

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Solution

The fourth proportional to 426.38, 639.56 and 137.81 is: 206.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.38 : 639.56 = 137.81 : x
  2. Step 2: Convert to fraction form
    426.38/639.56 = 137.81/x
  3. Step 3: Cross multiply
    426.38x = 639.56 × 137.81
  4. Step 4: Simplify right side
    426.38x = 88,139.71
  5. Step 5: Solve for x
    x = 88,139.71/426.38
  6. Step 6: Final answer
    x = 206.72

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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.