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Finding the Fourth Proportional to 685.95, 1,028.97 and 321.09

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Solution

The fourth proportional to 685.95, 1,028.97 and 321.09 is: 481.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.95 : 1,028.97 = 321.09 : x
  2. Step 2: Convert to fraction form
    685.95/1,028.97 = 321.09/x
  3. Step 3: Cross multiply
    685.95x = 1,028.97 × 321.09
  4. Step 4: Simplify right side
    685.95x = 330,391.98
  5. Step 5: Solve for x
    x = 330,391.98/685.95
  6. Step 6: Final answer
    x = 481.66

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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.