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Finding the Fourth Proportional to 640.39, 959.07 and 408.55

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Solution

The fourth proportional to 640.39, 959.07 and 408.55 is: 611.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.39 : 959.07 = 408.55 : x
  2. Step 2: Convert to fraction form
    640.39/959.07 = 408.55/x
  3. Step 3: Cross multiply
    640.39x = 959.07 × 408.55
  4. Step 4: Simplify right side
    640.39x = 391,828.23
  5. Step 5: Solve for x
    x = 391,828.23/640.39
  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.