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Finding the Fourth Proportional to 640.20, 958.78 and 408.37

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Solution

The fourth proportional to 640.20, 958.78 and 408.37 is: 611.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.20 : 958.78 = 408.37 : x
  2. Step 2: Convert to fraction form
    640.20/958.78 = 408.37/x
  3. Step 3: Cross multiply
    640.20x = 958.78 × 408.37
  4. Step 4: Simplify right side
    640.20x = 391,535.87
  5. Step 5: Solve for x
    x = 391,535.87/640.20
  6. Step 6: Final answer
    x = 611.58

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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.