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Finding the Fourth Proportional to 426.69, 639.90 and 138.06

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Solution

The fourth proportional to 426.69, 639.90 and 138.06 is: 207.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.69 : 639.90 = 138.06 : x
  2. Step 2: Convert to fraction form
    426.69/639.90 = 138.06/x
  3. Step 3: Cross multiply
    426.69x = 639.90 × 138.06
  4. Step 4: Simplify right side
    426.69x = 88,344.59
  5. Step 5: Solve for x
    x = 88,344.59/426.69
  6. Step 6: Final answer
    x = 207.05

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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.