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Finding the Fourth Proportional to 3,978, 5,488.74 and 2,405.78

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Solution

The fourth proportional to 3,978, 5,488.74 and 2,405.78 is: 3,319.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,978 : 5,488.74 = 2,405.78 : x
  2. Step 2: Convert to fraction form
    3,978/5,488.74 = 2,405.78/x
  3. Step 3: Cross multiply
    3,978x = 5,488.74 × 2,405.78
  4. Step 4: Simplify right side
    3,978x = 13,204,700.92
  5. Step 5: Solve for x
    x = 13,204,700.92/3,978
  6. Step 6: Final answer
    x = 3,319.43

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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.