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Finding the Fourth Proportional to 638.98, 881.78 and 355.38

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Solution

The fourth proportional to 638.98, 881.78 and 355.38 is: 490.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.98 : 881.78 = 355.38 : x
  2. Step 2: Convert to fraction form
    638.98/881.78 = 355.38/x
  3. Step 3: Cross multiply
    638.98x = 881.78 × 355.38
  4. Step 4: Simplify right side
    638.98x = 313,365.20
  5. Step 5: Solve for x
    x = 313,365.20/638.98
  6. Step 6: Final answer
    x = 490.41

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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.