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Finding the Fourth Proportional to 638.32, 879.78 and 490.36

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Solution

The fourth proportional to 638.32, 879.78 and 490.36 is: 675.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.32 : 879.78 = 490.36 : x
  2. Step 2: Convert to fraction form
    638.32/879.78 = 490.36/x
  3. Step 3: Cross multiply
    638.32x = 879.78 × 490.36
  4. Step 4: Simplify right side
    638.32x = 431,408.92
  5. Step 5: Solve for x
    x = 431,408.92/638.32
  6. Step 6: Final answer
    x = 675.85

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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.