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Finding the Fourth Proportional to 1,280.89, 1,768.49 and 861.87

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Solution

The fourth proportional to 1,280.89, 1,768.49 and 861.87 is: 1,189.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.89 : 1,768.49 = 861.87 : x
  2. Step 2: Convert to fraction form
    1,280.89/1,768.49 = 861.87/x
  3. Step 3: Cross multiply
    1,280.89x = 1,768.49 × 861.87
  4. Step 4: Simplify right side
    1,280.89x = 1,524,208.48
  5. Step 5: Solve for x
    x = 1,524,208.48/1,280.89
  6. Step 6: Final answer
    x = 1,189.96

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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.