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Finding the Fourth Proportional to 685.69, 1,028.89 and 439.03

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Solution

The fourth proportional to 685.69, 1,028.89 and 439.03 is: 658.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.69 : 1,028.89 = 439.03 : x
  2. Step 2: Convert to fraction form
    685.69/1,028.89 = 439.03/x
  3. Step 3: Cross multiply
    685.69x = 1,028.89 × 439.03
  4. Step 4: Simplify right side
    685.69x = 451,713.75
  5. Step 5: Solve for x
    x = 451,713.75/685.69
  6. Step 6: Final answer
    x = 658.77

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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.