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Finding the Fourth Proportional to 685.38, 1,028.13 and 198.43

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Solution

The fourth proportional to 685.38, 1,028.13 and 198.43 is: 297.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.38 : 1,028.13 = 198.43 : x
  2. Step 2: Convert to fraction form
    685.38/1,028.13 = 198.43/x
  3. Step 3: Cross multiply
    685.38x = 1,028.13 × 198.43
  4. Step 4: Simplify right side
    685.38x = 204,008.52
  5. Step 5: Solve for x
    x = 204,008.52/685.38
  6. Step 6: Final answer
    x = 297.66

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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.