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Finding the Fourth Proportional to 425.77, 638.66 and 137.21

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Solution

The fourth proportional to 425.77, 638.66 and 137.21 is: 205.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.77 : 638.66 = 137.21 : x
  2. Step 2: Convert to fraction form
    425.77/638.66 = 137.21/x
  3. Step 3: Cross multiply
    425.77x = 638.66 × 137.21
  4. Step 4: Simplify right side
    425.77x = 87,627.69
  5. Step 5: Solve for x
    x = 87,627.69/425.77
  6. Step 6: Final answer
    x = 205.81

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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.