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Finding the Fourth Proportional to 640.85, 884.13 and 391.97

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Solution

The fourth proportional to 640.85, 884.13 and 391.97 is: 540.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.85 : 884.13 = 391.97 : x
  2. Step 2: Convert to fraction form
    640.85/884.13 = 391.97/x
  3. Step 3: Cross multiply
    640.85x = 884.13 × 391.97
  4. Step 4: Simplify right side
    640.85x = 346,552.44
  5. Step 5: Solve for x
    x = 346,552.44/640.85
  6. Step 6: Final answer
    x = 540.77

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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.