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Finding the Fourth Proportional to 3,138.78, 4,707.85 and 1,905.85

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Solution

The fourth proportional to 3,138.78, 4,707.85 and 1,905.85 is: 2,858.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,138.78 : 4,707.85 = 1,905.85 : x
  2. Step 2: Convert to fraction form
    3,138.78/4,707.85 = 1,905.85/x
  3. Step 3: Cross multiply
    3,138.78x = 4,707.85 × 1,905.85
  4. Step 4: Simplify right side
    3,138.78x = 8,972,455.92
  5. Step 5: Solve for x
    x = 8,972,455.92/3,138.78
  6. Step 6: Final answer
    x = 2,858.58

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.