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Finding the Fourth Proportional to 640.89, 883.99 and 391.89

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Solution

The fourth proportional to 640.89, 883.99 and 391.89 is: 540.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.89 : 883.99 = 391.89 : x
  2. Step 2: Convert to fraction form
    640.89/883.99 = 391.89/x
  3. Step 3: Cross multiply
    640.89x = 883.99 × 391.89
  4. Step 4: Simplify right side
    640.89x = 346,425.86
  5. Step 5: Solve for x
    x = 346,425.86/640.89
  6. Step 6: Final answer
    x = 540.54

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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.