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Finding the Fourth Proportional to 640.20, 883.26 and 391.38

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Solution

The fourth proportional to 640.20, 883.26 and 391.38 is: 539.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.20 : 883.26 = 391.38 : x
  2. Step 2: Convert to fraction form
    640.20/883.26 = 391.38/x
  3. Step 3: Cross multiply
    640.20x = 883.26 × 391.38
  4. Step 4: Simplify right side
    640.20x = 345,690.30
  5. Step 5: Solve for x
    x = 345,690.30/640.20
  6. Step 6: Final answer
    x = 539.97

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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.