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Finding the Fourth Proportional to 640.69, 883.92 and 391.92

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Solution

The fourth proportional to 640.69, 883.92 and 391.92 is: 540.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.69 : 883.92 = 391.92 : x
  2. Step 2: Convert to fraction form
    640.69/883.92 = 391.92/x
  3. Step 3: Cross multiply
    640.69x = 883.92 × 391.92
  4. Step 4: Simplify right side
    640.69x = 346,425.93
  5. Step 5: Solve for x
    x = 346,425.93/640.69
  6. Step 6: Final answer
    x = 540.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.