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Finding the Fourth Proportional to 426.62, 639.99 and 138.05

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Solution

The fourth proportional to 426.62, 639.99 and 138.05 is: 207.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.62 : 639.99 = 138.05 : x
  2. Step 2: Convert to fraction form
    426.62/639.99 = 138.05/x
  3. Step 3: Cross multiply
    426.62x = 639.99 × 138.05
  4. Step 4: Simplify right side
    426.62x = 88,350.62
  5. Step 5: Solve for x
    x = 88,350.62/426.62
  6. Step 6: Final answer
    x = 207.09

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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.