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Finding the Fourth Proportional to 685.89, 1,028.85 and 198.95

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Solution

The fourth proportional to 685.89, 1,028.85 and 198.95 is: 298.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.89 : 1,028.85 = 198.95 : x
  2. Step 2: Convert to fraction form
    685.89/1,028.85 = 198.95/x
  3. Step 3: Cross multiply
    685.89x = 1,028.85 × 198.95
  4. Step 4: Simplify right side
    685.89x = 204,684.56
  5. Step 5: Solve for x
    x = 204,684.56/685.89
  6. Step 6: Final answer
    x = 298.42

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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.