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Finding the Fourth Proportional to 640.39, 959.06 and 408.56

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Solution

The fourth proportional to 640.39, 959.06 and 408.56 is: 611.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.39 : 959.06 = 408.56 : x
  2. Step 2: Convert to fraction form
    640.39/959.06 = 408.56/x
  3. Step 3: Cross multiply
    640.39x = 959.06 × 408.56
  4. Step 4: Simplify right side
    640.39x = 391,830.55
  5. Step 5: Solve for x
    x = 391,830.55/640.39
  6. Step 6: Final answer
    x = 611.86

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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.