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Finding the Fourth Proportional to 685.15, 1,027.78 and 198.21

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Solution

The fourth proportional to 685.15, 1,027.78 and 198.21 is: 297.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.15 : 1,027.78 = 198.21 : x
  2. Step 2: Convert to fraction form
    685.15/1,027.78 = 198.21/x
  3. Step 3: Cross multiply
    685.15x = 1,027.78 × 198.21
  4. Step 4: Simplify right side
    685.15x = 203,716.27
  5. Step 5: Solve for x
    x = 203,716.27/685.15
  6. Step 6: Final answer
    x = 297.33

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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.