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Finding the Fourth Proportional to 426.55, 639.68 and 137.89

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Solution

The fourth proportional to 426.55, 639.68 and 137.89 is: 206.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.55 : 639.68 = 137.89 : x
  2. Step 2: Convert to fraction form
    426.55/639.68 = 137.89/x
  3. Step 3: Cross multiply
    426.55x = 639.68 × 137.89
  4. Step 4: Simplify right side
    426.55x = 88,204.79
  5. Step 5: Solve for x
    x = 88,204.79/426.55
  6. Step 6: Final answer
    x = 206.79

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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.