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Finding the Fourth Proportional to 1,391.30, 2,087.97 and 660.87

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Solution

The fourth proportional to 1,391.30, 2,087.97 and 660.87 is: 991.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.30 : 2,087.97 = 660.87 : x
  2. Step 2: Convert to fraction form
    1,391.30/2,087.97 = 660.87/x
  3. Step 3: Cross multiply
    1,391.30x = 2,087.97 × 660.87
  4. Step 4: Simplify right side
    1,391.30x = 1,379,876.73
  5. Step 5: Solve for x
    x = 1,379,876.73/1,391.30
  6. Step 6: Final answer
    x = 991.79

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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.