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Finding the Fourth Proportional to 426.40, 639.62 and 137.86

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Solution

The fourth proportional to 426.40, 639.62 and 137.86 is: 206.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.40 : 639.62 = 137.86 : x
  2. Step 2: Convert to fraction form
    426.40/639.62 = 137.86/x
  3. Step 3: Cross multiply
    426.40x = 639.62 × 137.86
  4. Step 4: Simplify right side
    426.40x = 88,174.13
  5. Step 5: Solve for x
    x = 88,174.13/426.40
  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.