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Finding the Fourth Proportional to 1,078.87, 1,618.31 and 861.43

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Solution

The fourth proportional to 1,078.87, 1,618.31 and 861.43 is: 1,292.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.87 : 1,618.31 = 861.43 : x
  2. Step 2: Convert to fraction form
    1,078.87/1,618.31 = 861.43/x
  3. Step 3: Cross multiply
    1,078.87x = 1,618.31 × 861.43
  4. Step 4: Simplify right side
    1,078.87x = 1,394,060.78
  5. Step 5: Solve for x
    x = 1,394,060.78/1,078.87
  6. Step 6: Final answer
    x = 1,292.15

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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.